basis-a.lisp

; ACL2 Version 8.4 -- A Computational Logic for Applicative Common Lisp
; Copyright (C) 2022, Regents of the University of Texas

; This version of ACL2 is a descendent of ACL2 Version 1.9, Copyright
; (C) 1997 Computational Logic, Inc.  See the documentation topic NOTE-2-0.

; This program is free software; you can redistribute it and/or modify
; it under the terms of the LICENSE file distributed with ACL2.

; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
; LICENSE for more details.

; Written by:  Matt Kaufmann               and J Strother Moore
; email:       Kaufmann@cs.utexas.edu      and Moore@cs.utexas.edu
; Department of Computer Science
; University of Texas at Austin
; Austin, TX 78712 U.S.A.

; The code in this file was originally placed in several different source
; files, but was moved here in order to support the creation of "toothbrush"
; applications -- that is, so that fewer ACL2 source files need to be loaded in
; order to support ACL2 applications.  See community books file
; books/system/toothbrush/README.

(in-package "ACL2")

; Case-match

(defun equal-x-constant (x const)

; x is an arbitrary term, const is a quoted constant, e.g., a list of
; the form (QUOTE guts).  We return a term equivalent to (equal x
; const).

  (declare (xargs :guard (and (consp const)
                              (eq (car const) 'quote)
                              (consp (cdr const)))))
  (let ((guts (cadr const)))
    (cond ((symbolp guts)
           (list 'eq x const))
          ((or (acl2-numberp guts)
               (characterp guts))
           (list 'eql x guts))
          ((stringp guts)
           (list 'equal x guts))
          (t (list 'equal x const)))))

(defun match-tests-and-bindings (x pat tests bindings)

; We return two results.  The first is a list of tests, in reverse
; order, that determine whether x matches the structure pat.  We
; describe the language of pat below.  The tests are accumulated onto
; tests, which should be nil initially.  The second result is an alist
; containing entries of the form (sym expr), suitable for use as the
; bindings in the let we generate if the tests are satisfied.  The
; bindings required by pat are accumulated onto bindings and thus are
; reverse order, although their order is actually irrelevant.

; For example, the pattern
;   ('equal ('car ('cons u v)) u)
; matches only first order instances of (EQUAL (CAR (CONS u v)) u).

; The pattern
;   ('equal (ev (simp x) a) (ev x a))
; matches only second order instances of (EQUAL (ev (simp x) a) (ev x a)),
; i.e., ev, simp, x, and a are all bound in the match.

; In general, the match requires that the cons structure of x be isomorphic
; to that of pat, down to the atoms in pat.  Symbols in the pat denote
; variables that match anything and get bound to the structure matched.
; Occurrences of a symbol after the first match only structures equal to
; the binding.  Non-symbolp atoms match themselves.

; There are some exceptions to the general scheme described above.  A cons
; structure starting with QUOTE matches only itself.  A cons structure of the
; form (QUOTE~ sym), where sym is a symbol, is like (QUOTE sym) except it
; matches any symbol with the same symbol-name as sym.  The symbols nil and t,
; and all symbols whose symbol-name starts with #\* match only structures equal
; to their values.  (These symbols cannot be legally bound in ACL2 anyway, so
; this exceptional treatment does not restrict us further.)  Any symbol
; starting with #\! matches only the value of the symbol whose name is obtained
; by dropping the #\!.  This is a way of referring to already bound variables
; in the pattern. Finally, the symbol & matches anything and causes no binding.

  (declare (xargs :guard (symbol-doublet-listp bindings)))
  (cond
   ((symbolp pat)
    (cond
     ((or (eq pat t)
          (eq pat nil)
          (keywordp pat))
      (mv (cons (list 'eq x pat) tests) bindings))
     ((let ((len (length (symbol-name pat))))
        (and (> len 0)
             (eql #\* (char (symbol-name pat) 0))
             (eql #\* (char (symbol-name pat) (1- len)))))
      (mv (cons (list 'equal x pat) tests) bindings))
     ((and (> (length (symbol-name pat)) 0)
           (eql #\! (char (symbol-name pat) 0)))
      (mv (cons (list 'equal x
                      (intern-in-package-of-symbol
                       (subseq (symbol-name pat)
                               1
                               (length (symbol-name pat)))
                       pat))
                tests)
          bindings))
     ((eq pat '&) (mv tests bindings))
     (t (let ((binding (assoc-eq pat bindings)))
          (cond ((null binding)
                 (mv tests (cons (list pat x) bindings)))
                (t (mv (cons (list 'equal x (cadr binding)) tests)
                       bindings)))))))
   ((atom pat)
    (mv (cons (equal-x-constant x (list 'quote pat)) tests)
        bindings))
   ((and (eq (car pat) 'quote)
         (consp (cdr pat))
         (null (cddr pat)))
    (mv (cons (equal-x-constant x pat) tests)
        bindings))
   ((and (eq (car pat) 'quote~)
         (consp (cdr pat))
         (symbolp (cadr pat))
         (null (cddr pat)))
    (mv (cons (list 'symbol-name-equal x (symbol-name (cadr pat))) tests)
        bindings))
   (t (mv-let (tests1 bindings1)
        (match-tests-and-bindings (list 'car x) (car pat)
                                  (cons (list 'consp x) tests)
                                  bindings)
        (match-tests-and-bindings (list 'cdr x) (cdr pat)
                                  tests1 bindings1)))))
(defun match-clause (x pat forms)
  (declare (xargs :guard t))
  (mv-let (tests bindings)
    (match-tests-and-bindings x pat nil nil)
    (list (if (null tests)
              t
            (cons 'and (reverse tests)))
          (cons 'let (cons (reverse bindings) forms)))))

(defun match-clause-list (x clauses)
  (declare (xargs :guard (alistp clauses)))
  (cond ((consp clauses)
         (if (eq (caar clauses) '&)
             (list (match-clause x (caar clauses) (cdar clauses)))
           (cons (match-clause x (caar clauses) (cdar clauses))
                 (match-clause-list x (cdr clauses)))))
        (t '((t nil)))))

(defmacro case-match (&rest args)
  (declare (xargs :guard (and (consp args)
                              (symbolp (car args))
                              (alistp (cdr args))
                              (null (cdr (member-equal (assoc-eq '& (cdr args))
                                                       (cdr args)))))))
  (cons 'cond (match-clause-list (car args) (cdr args))))

; Essay on Wormholes

; Once upon a time (Version  3.6 and earlier) the wormhole function had a
; pseudo-flg argument which allowed the user a quick way to determine whether
; it was appropriate to incur the expense of going into the wormhole.  The idea
; was that the form could have one a free var in it, wormhole-output, and that
; when it was evaluated in raw Lisp that variable was bound to the last value
; returned by the wormhole.  Since wormhole always returned nil anyway, this
; screwy semantics didn't matter.  However, it was implemented in such a way
; that a poorly constructed pseudo-flg could survive guard verification and yet
; cause a hard error at runtime because during guard verification
; wormhole-output was bound to NIL but in actual evaluation it was entirely
; under the control of the wormhole forms.

; To fix this we have introduced wormhole-eval.  It takes two important
; arguments, the name of the wormhole and a lambda expression.  Both must be
; quoted.  The lambda may have at most one argument but the body may contain
; any variables available in the environment of the wormhole-eval call.  (A
; third argument to wormhole-eval is an arbitrary form that uses all the free
; vars of the lambda, thus insuring that translate will cause an error if the
; lambda uses variables unavailable in the context.)  The body of the lambda
; must be a single-valued, non-state, non-stobj term.

; The idea is that the lambda expression is applied to the last value of the
; wormhole output and its value is assigned as the last value of the wormhole
; output.  Wormhole-eval always returns nil.  Translation of a wormhole-eval
; call enforces these restrictions.  Furthermore, it translates the body of the
; lambda (even though the lambda is quoted).  This is irrelevant since the
; wormhole-eval returns nil regardless of the lambda expression supplied.
; Similarly, translation computes an appropriate third argument to use all the
; free vars, so the user may just write nil there and a suitable form is
; inserted by translate.

; We arrange for wormhole-eval to be a macro in raw lisp that really does what
; is said above.

; To make it bullet-proof, when we generate guard clauses we go inside the
; lambda, generating a new variable symbol to use in place of the lambda formal
; denoting the last value of the wormhole output.  Thus, if guard clauses can be
; verified, it doesn't matter what the wormhole actually returns as its value.

; Ev-rec, the interpreter for terms, treats wormhole-eval specially in the
; expected way, as does oneify.  Thus, both interpreted and compiled calls of
; wormhole-eval are handled, and guard violations are handled politely.

; Now, how does this allow us to fix the wormhole pseudo-flg problem?

; The hidden global variable in Lisp used to record the status of the various
; wormholes is called *wormhole-status-alist*.  The entry in this alist for
; a particular wormhole will be called the wormhole's ``status.''  The lambda
; expression in wormhole-eval maps the wormhole's status to a new status.

; The status of a wormhole is supposed to be a cons whose car is either :ENTER
; or :SKIP.  However, in the absence of verifying the guards on the code inside
; wormholes and in light of the fact that users can set the status by
; manipulating wormhole-status in the wormhole it is hard to ensure that the
; status is always as supposed.  So we code rather defensively.

; When the ``function'' wormhole is called it may or may not actually enter a
; wormhole.  ``Entering'' the wormhole means invoking the form on the given
; input, inside a side-effects undoing call of ld.  That, in turn, involves
; setting up the ld specials and then reading, translating, and evaluating
; forms.  Upon exit, cleanup must be done.  So entering is expensive.

; Whether it enters the wormhole or not depends on the wormhole's status, and
; in particular it depends on what we call the wormhole's ``entry code''
; computed from the status as follows.

; If the wormhole's status satisfies wormhole-statusp then the situation is
; simple: wormhole enters the wormhole if the status is :ENTER and doesn't if
; the status is :SKIP.  But we compute the entry code defensively: the entry
; code is :SKIP if and only if the wormhole's status is a cons whose car is
; :SKIP.  Otherwise, the entry code is :ENTER.

; If we enter the wormhole, we take the wormhole input argument and stuff it
; into (@ wormhole-input), allowing the user to see it inside the ld code.  We
; take the wormhole status and stuff it into (@ wormhole-status), allowing the
; user to see it and probably change it with (assign wormhole-status...).  When
; we exit ld, we take (@ wormhole-status) and put it back into the hidden
; *wormhole-status-alist*.

; One subtlety arises: How to make wormholes re-entrant...  The problem is that
; sometimes the current status is in the hidden alist and other times it is in
; (@ wormhole-status).  So when we try to enter a new wormhole from within a
; wormhole -- which always happens by calling wormhole-eval -- the first thing
; we do is stuff the current (@ wormhole-status) into the hidden
; *wormhole-status-alist*.  This means that the lambda expression for the new
; entrance is applied, it is applied to the ``most recent'' value of the status
; of that particular wormhole.  The natural undoing of wormhole effects
; implements the restoration of (@ wormhole-status) upon exit from the
; recursive wormhole.

; If we wanted to convert our system code to logic mode we would want to verify
; the guards of the lambda bodies and the wormhole-status after ld.  See the
; comment in push-accp.  Here is a proposal for how to do that.  First, insist
; that wormhole names are symbols.  Indeed, they must be one argument,
; guard-verified Boolean functions.  The guard for a call of wormhole-eval on a
; wormhole named foo should include the conjunct (foo nil) to ensure that the
; initial value of the status is acceptable.  The guard on the body of (lambda
; (whs) body) should be extended to include the hypothesis that (foo whs) is
; true and that (foo whs) --> (foo body) is true.  We should then change
; wormhole so that if it calls ld it tests foo at runtime after the ld returns
; so we know that the final status satisfies foo.  If we do this we can safely
; assume that every status seen by a lambda body in wormhole-eval will satisfy
; the foo invariant.

(defun wormhole-statusp (whs)
  (declare (xargs :mode :logic :guard t))
  (or (equal whs nil)
      (and (consp whs)
           (or (eq (car whs) :ENTER)
               (eq (car whs) :SKIP)))))

(defun wormhole-entry-code (whs)

; Keep this function in sync with the inline code in wormhole1.

  (declare (xargs :mode :logic :guard t))
  (if (and (consp whs)
           (eq (car whs) :SKIP))
      :SKIP
      :ENTER))

(defun wormhole-data (whs)
  (declare (xargs :mode :logic :guard t))
  (if (consp whs)
      (cdr whs)
      nil))

(defun set-wormhole-entry-code (whs code)
  (declare (xargs :mode :logic
                  :guard (or (eq code :ENTER)
                             (eq code :SKIP))))
  (if (consp whs)
      (if (eq (car whs) code)
          whs
          (cons code (cdr whs)))
      (if (eq code :enter)
          whs
          (cons :skip whs))))

(defun set-wormhole-data (whs data)
  (declare (xargs :mode :logic :guard t))
  (if (consp whs)
      (if (equal (cdr whs) data)
          whs
          (cons (car whs) data))
      (cons :enter data)))

(defun make-wormhole-status (old-status new-code new-data)
  (declare (xargs :mode :logic
                  :guard (or (eq new-code :ENTER)
                             (eq new-code :SKIP))))
  (if (consp old-status)
      (if (and (eq new-code (car old-status))
               (equal new-data (cdr old-status)))
          old-status
          (cons new-code new-data))
      (cons new-code new-data)))

; (defthm wormhole-status-guarantees
;   (if (or (eq code :enter)
;           (eq code :skip))
;       (and (implies (wormhole-statusp whs)
;                     (wormhole-statusp (set-wormhole-entry-code whs code)))
;            (implies (wormhole-statusp whs)
;                     (wormhole-statusp (set-wormhole-data whs data)))
;            (equal (wormhole-entry-code (set-wormhole-entry-code whs code))
;                   code)
;            (equal (wormhole-data (set-wormhole-data whs data))
;                   data)
;            (implies (wormhole-statusp whs)
;                     (equal (wormhole-data (set-wormhole-entry-code whs code))
;                            (wormhole-data whs)))
;            (implies (wormhole-statusp whs)
;                     (equal (wormhole-entry-code
;                             (set-wormhole-data whs data))
;                            (wormhole-entry-code whs)))
;            (implies (wormhole-statusp whs)
;                     (wormhole-statusp (make-wormhole-status whs code data)))
;            (equal (wormhole-entry-code (make-wormhole-status whs code data))
;                   code)
;            (equal (wormhole-data (make-wormhole-status whs code data))
;                   data))
;       t)
;   :rule-classes nil)
;
; (verify-guards wormhole-status-guarantees)

; In particular, given a legal code, set-wormhole-entry-code preserves
; wormhole-statusp and always returns an object with the given entry code
; (whether the status was well-formed or not).  Furthermore, the guards on
; these functions are verified.  Thus, they can be called safely even if the
; user has messed up our wormhole status.  Of course, if the user has messed up
; the status, there is no guarantee about what happens inside the wormhole.

(defun tree-occur-eq (x y)

; Does symbol x occur in the cons tree y?

  (declare (xargs :guard (symbolp x)))
  (cond ((consp y)
         (or (tree-occur-eq x (car y))
             (tree-occur-eq x (cdr y))))
        (t (eq x y))))

#+acl2-loop-only
(defun wormhole-eval (qname qlambda free-vars)

; A typical call of this function is
; (wormhole-eval 'my-wormhole
;                '(lambda (output) (p x y output))
;                (list x y))

; And the pragmatic semantics is that the lambda expression is applied to the
; last output of the wormhole my-wormhole, the result of of the application is
; stuffed back in as the last output, and the function logically returns nil.
; Note that free vars in the lambda must listed.  This is so that the free vars
; of this wormhole-eval expression consists of the free vars of the lambda,
; even though the lambda appears quoted.  Translate automatically replaces the
; lambda expression constant by the translated version of that same constant,
; and it replaces the supposed list of free vars by the actual free vars.  So
; in fact the user calling wormhole-eval can just put nil in the free-vars arg
; and let translate fill it in.  Translate can mangle the arguments of
; wormhole-eval because it always returns nil, regardless of its arguments.

; The guard is declared below to be t but actually we compute the guard for the
; body of the quoted lambda, with some fiddling about the bound variable.

; (Remember: the quoted lambda of wormhole-eval is unrelated to apply$.)

  (declare (xargs :mode :logic
                  :guard t)
           (ignore qname qlambda free-vars))


  nil)

(deflock *wormhole-lock*)

#-acl2-loop-only
(defun put-assoc-equal-destructive (key val alist)
  (let ((pair (assoc-equal key alist)))
    (cond (pair (setf (cdr pair) val)
                alist)
          (t (acons key val alist)))))

(defun wormhole-eval-early-null-exit-p (qlambda)

; This function recognizes quoted lambdas that are subject to the wormhole-eval
; optimization of returning immediately when the wormhole-data is nil, which is
; reasonable since the old and new status are then equal.

  (case-match qlambda
    (('quote ('lambda (whs)
               ('let ((info ('wormhole-data whs)))
                 ('cond (('null info) whs) . &))))
     (declare (ignore info whs))
     t)
    (& nil)))

#-acl2-loop-only
(defmacro wormhole-eval (qname qlambda free-vars)
  (declare (xargs :guard t))

; All calls of wormhole-eval that have survived translation are of a special
; form.  Qname is a quoted object (used as the name of a wormhole), and qlambda
; is of one of the two forms:

; (i)  (quote (lambda (whs) body)), or
; (ii) (quote (lambda ()    body))

; where whs (``wormhole status'') is a legal variable symbol, body is a fully
; translated term that may involve whs and other variables which returns one
; result.  We furthermore know that the free vars in the lambda are the free
; vars of the term free-vars, which is typically just a list-expression of
; variable names supplied by translate.  Finally, we know that whs appears as
; the lambda formal iff it is used in body.

; Wormholes may have arbitrary objects for names, so qname is not necessarily a
; quoted symbol.  This may be the first entry into the wormhole of that name,
; in which case the most recent output of the wormhole is understood to be nil.

; Logically this function always returns nil.  Actually, it applies the lambda
; expression to either (i) ``the most recent output'' of the named wormhole or
; (ii) no arguments, appropriately, and stores the result as the most recent
; output, and then returns nil.

; For efficiency we use put-assoc-equal-destructive below instead of put-assoc.
; When considering a similar use of put-assoc-equal-destructive elsewhere --
; specifically, in ev-rec and in a cleanup form in wormhole1 -- then we should
; think about whether locks might be needed for ACL2(p).  We do have a lock
; here, by default.

  (let* ((whs (car (cadr (cadr qlambda)))) ; non-nil in Case (i) only
         (early-null-exit-p (and whs
                                 (wormhole-eval-early-null-exit-p qlambda)))
         (val (gensym))
         (form1
          `(progn
             (cond (*wormholep*
                    (setq *wormhole-status-alist*
                          (put-assoc-equal-destructive
                           (f-get-global 'wormhole-name
                                         *the-live-state*)
                           (f-get-global 'wormhole-status
                                         *the-live-state*)
                           *wormhole-status-alist*))))
             (let* ((*wormholep* t)
                    ,@(and whs ; Case (i)
                           (not early-null-exit-p) ; otherwise bind whs later
                           `((,whs
                              (cdr (assoc-equal ,qname
                                                *wormhole-status-alist*)))))
                    (,val ,(caddr (cadr qlambda))))

; At one time we skipped the following setq in the case that (equal ,whs ,val),
; where ,whs was unconditionally bound above.  However, that equality test can
; be expensive, so we avoid it.

               (setq *wormhole-status-alist*
                     (put-assoc-equal-destructive ,qname
                                                  ,val
                                                  *wormhole-status-alist*))
               nil)))
         (form2 (cond ((tree-occur-eq :no-wormhole-lock free-vars)
                       form1)
                      (t `(with-wormhole-lock ,form1)))))
    (cond (early-null-exit-p ; hence whs is non-nil
           `(let ((,whs (cdr (assoc-equal ,qname
                                          *wormhole-status-alist*))))
              (cond ((null (wormhole-data ,whs))

; Wormhole-data doesn't change (see wormhole-eval-early-null-exit-p), so we
; simply return.

                     nil)
                    (t ,form2))))
          (t form2))))

(defmacro wormhole (name entry-lambda input form
                         &key
                         (current-package 'same current-packagep)
                         (useless-runes 'same useless-runesp)
                         (ld-skip-proofsp 'same ld-skip-proofspp)
                         (ld-redefinition-action 'save ld-redefinition-actionp)
                         (ld-prompt ''wormhole-prompt)
                         (ld-missing-input-ok 'same ld-missing-input-okp)
                         (ld-pre-eval-filter 'same ld-pre-eval-filterp)
                         (ld-pre-eval-print 'same ld-pre-eval-printp)
                         (ld-post-eval-print 'same ld-post-eval-printp)
                         (ld-evisc-tuple 'same ld-evisc-tuplep)
                         (ld-error-triples 'same ld-error-triplesp)
                         (ld-error-action 'same ld-error-actionp)
                         (ld-query-control-alist 'same ld-query-control-alistp)
                         (ld-verbose 'same ld-verbosep)
                         (ld-user-stobjs-modified-warning ':same))

; Warning: Keep this in sync with f-get-ld-specials, f-put-ld-specials,
; *initial-ld-special-bindings*, ld-alist-raw, chk-acceptable-ld-fn1-pair, and
; ld.

  `(with-wormhole-lock
    (prog2$
     (wormhole-eval ,name ,entry-lambda

; It is probably harmless to allow a second lock under the one above, but there
; is no need, so we avoid it.

                    :no-wormhole-lock)
     (wormhole1
      ,name
      ,input
      ,form
      (list
       ,@(append
          (if current-packagep
              (list `(cons 'current-package ,current-package))
            nil)
          (if useless-runesp
              (list `(cons 'useless-runes ,useless-runes))
            nil)
          (if ld-skip-proofspp
              (list `(cons 'ld-skip-proofsp ,ld-skip-proofsp))
            nil)
          (if ld-redefinition-actionp
              (list `(cons 'ld-redefinition-action
                           ,ld-redefinition-action))
            nil)
          (list `(cons 'ld-prompt ,ld-prompt))
          (if ld-missing-input-okp
              (list `(cons 'ld-missing-input-ok ,ld-missing-input-ok))
            nil)
          (if ld-pre-eval-filterp
              (list `(cons 'ld-pre-eval-filter ,ld-pre-eval-filter))
            nil)
          (if ld-pre-eval-printp
              (list `(cons 'ld-pre-eval-print ,ld-pre-eval-print))
            nil)
          (if ld-post-eval-printp
              (list `(cons 'ld-post-eval-print ,ld-post-eval-print))
            nil)
          (if ld-evisc-tuplep
              (list `(cons 'ld-evisc-tuple ,ld-evisc-tuple))
            nil)
          (if ld-error-triplesp
              (list `(cons 'ld-error-triples ,ld-error-triples))
            nil)
          (if ld-error-actionp
              (list `(cons 'ld-error-action ,ld-error-action))
            nil)
          (if ld-query-control-alistp
              (list `(cons 'ld-query-control-alist ,ld-query-control-alist))
            nil)
          (if ld-verbosep
              (list `(cons 'ld-verbose ,ld-verbose))
            nil)
          (if (eq ld-user-stobjs-modified-warning :same)
              (list `(cons 'ld-user-stobjs-modified-warning
                           ,ld-user-stobjs-modified-warning))
            nil)))))))

(defun lambda-keywordp (x)
  (and (symbolp x)
       (eql 1 (string<= "&" (symbol-name x)))))

(defun legal-variable-or-constant-namep (name)

; This function checks the syntax of variable or constant name
; symbols.  In all cases, name must be a symbol that is not in the
; keyword package or among *common-lisp-specials-and-constants*
; (except t and nil), or in the main Lisp package but outside
; *common-lisp-symbols-from-main-lisp-package*, and that does not
; start with an ampersand.  The function returns 'constant, 'variable,
; or nil.

; WARNING: T and nil are legal-variable-or-constant-nameps
; because we want to allow their use as constants.

; We now allow some variables (but still no constants) from the main Lisp
; package.  See *common-lisp-specials-and-constants*.  The following note
; explains why we have been cautious here.

; Historical Note

; This package restriction prohibits using some very common names as
; variables or constants, e.g., MAX and REST.  Why do we do this?  The
; reason is that there are a few such symbols, such as
; LAMBDA-LIST-KEYWORDS, which if bound or set could cause real
; trouble.  Rather than attempt to identify all of the specials of
; CLTL that are prohibited as ACL2 variables, we just prohibit them
; all.  One might be reminded of Alexander cutting the Gordian Knot.
; We could spend a lot of time unraveling complex questions about
; specials in CLTL or we can get on with it.  When ACL2 prevents you
; from using REST as an argument, you should see the severed end of a
; once tangled rope.

; For example, akcl and lucid (and others perhaps) allow you to define
; (defun foo (boole-c2) boole-c2) but then (foo 3) causes an error.
; Note that boole-c2 is recognized as special (by
; system::proclaimed-special-p) in lucid, but not in akcl (by
; si::specialp); in fact it's a constant in both.  Ugh.

; End of Historical Note.

  (and (symbolp name)
       (cond
        ((or (eq name t) (eq name nil))
         'constant)
        (t (let ((p (symbol-package-name name)))
             (and (not (equal p "KEYWORD"))
                  (let ((s (symbol-name name)))
                    (cond
                     ((and (not (= (length s) 0))
                           (eql (char s 0) #\*)
                           (eql (char s (1- (length s))) #\*))

; It was an oversight that a symbol with a symbol-name of "*" has always been
; considered a constant rather than a variable.  The intention was to view "*"
; as a delimiter -- thus, even "**" is probably OK for a constant since the
; empty string is delimited.  But it doesn't seem important to change this
; now.  If we do make such a change, consider the following (at least).

; - Be sure to rule out * in any package as a stobj name, since in a signature,
;   such a symbol denotes a non-stobj (see for example collect-non-* and see
;   mentions of "*" in functions that involve signatures).

; - It will be necessary to update :doc defconst.

; - Fix the error message for, e.g., (defconst foo::* 17), so that it doesn't
;   say "does not begin and end with the character *".

; - Make sure the error message is correct for (defun foo (*) *).  It should
;   probably complain about the main Lisp package, not about "the syntax of a
;   constant".

                      (if (equal p *main-lisp-package-name*)
                          nil
                        'constant))
                     ((and (not (= (length s) 0))
                           (eql (char s 0) #\&))
                      nil)
                     ((equal p *main-lisp-package-name*)
                      (and (not (member-eq
                                 name
                                 *common-lisp-specials-and-constants*))
                           (member-eq
                            name
                            *common-lisp-symbols-from-main-lisp-package*)
                           'variable))
                     (t 'variable)))))))))

(defun legal-variablep (name)

; Name may be used as a variable if it has the syntax of a variable
; (see legal-variable-or-constant-namep) and does not have the syntax of
; a constant, i.e., does not start and end with a *.

  (eq (legal-variable-or-constant-namep name) 'variable))

(defun arglistp1 (lst)

; Every element of lst is a legal-variablep.

  (cond ((atom lst) (null lst))
        (t (and (legal-variablep (car lst))
                (arglistp1 (cdr lst))))))

(defun arglistp (lst)
  (and (arglistp1 lst)
       (no-duplicatesp-eq lst)))

(defun find-first-bad-arg (args)

; This function is only called when args is known to be a non-arglistp
; that is a true list.  It returns the first bad argument and a string
; that completes the phrase "... violates the rules because it ...".

  (declare (xargs :guard (and (true-listp args)
                              (not (arglistp args)))))
  (cond
   ;;((null args) (mv nil nil)) -- can't happen, given the guard!
   ((not (symbolp (car args))) (mv (car args) "is not a symbol"))
   ((legal-constantp1 (car args))
    (mv (car args) "has the syntax of a constant"))
   ((lambda-keywordp (car args))
    (mv (car args) "is a lambda keyword"))
   ((keywordp (car args))
    (mv (car args) "is in the KEYWORD package"))
   ((member-eq (car args) *common-lisp-specials-and-constants*)
    (mv (car args) "belongs to the list *common-lisp-specials-and-constants* ~
                    of symbols from the main Lisp package"))
   ((member-eq (car args) (cdr args))
    (mv (car args) "occurs more than once in the list"))
   ((and (equal (symbol-package-name (car args)) *main-lisp-package-name*)
         (not (member-eq (car args)
                         *common-lisp-symbols-from-main-lisp-package*)))
    (mv (car args) "belongs to the main Lisp package but not to the list ~
                    *common-lisp-symbols-from-main-lisp-package*"))
   (t (find-first-bad-arg (cdr args)))))

(defun process-defabbrev-declares (decls)
  (cond ((endp decls) ())

; Here we do a cheap check that the declare form is illegal.  It is tempting to
; use collect-declarations, but it take state.  Anyhow, there is no soundness
; issue; the user will just be a bit surprised when the error shows up later as
; the macro defined by the defabbrev is applied.

        ((not (and (consp (car decls))
                   (eq (caar decls) 'DECLARE)
                   (true-list-listp (cdar decls))
                   (subsetp-eq (strip-cars (cdar decls))
                               '(IGNORE IGNORABLE TYPE))))
         (er hard 'process-defabbrev-declares
             "In a DEFABBREV form, each expression after the argument list ~
              but before the body must be of the form (DECLARE decl1 .. ~
              declk), where each dcli is of the form (IGNORE ..), (IGNORABLE ~
              ..), or (TYPE ..).  The form ~x0 is thus illegal."
             (car decls)))
        (t
         (cons (kwote (car decls))
               (process-defabbrev-declares (cdr decls))))))

(defun defabbrev1 (lst)
  (declare (xargs :guard (true-listp lst)))
  (cond ((null lst) nil)
        (t (cons (list 'list (list 'quote (car lst)) (car lst))
                 (defabbrev1 (cdr lst))))))

(defmacro defabbrev (fn args &rest body)
  (cond ((null body)
         (er hard (cons 'defabbrev fn)
             "The body of this DEFABBREV form is missing."))
        ((not (true-listp args))
         (er hard (cons 'defabbrev fn)
             "The formal parameter list for a DEFABBREV must be a true list.  ~
              The argument list ~x0 is thus illegal."
             args))
        ((not (arglistp args))
         (mv-let (culprit explan)
                 (find-first-bad-arg args)
                 (er hard (cons 'defabbrev fn)
                     "The formal parameter list for a DEFABBREV must be a ~
                      list of distinct variables, but ~x0 does not meet these ~
                      conditions.  The element ~x1 ~@2."
                     args culprit explan)))
        (t
         (mv-let (doc-string-list body)
                 (if (and (stringp (car body))
                          (cdr body))
                     (mv (list (car body)) (cdr body))
                   (mv nil body))
                 (cond ((null body)
                        (er hard (cons 'defabbrev fn)
                            "This DEFABBREV form has a doc string but no ~
                             body."))
                       ((and (consp (car (last body)))
                             (eq (caar (last body)) 'declare))
                        (er hard (cons 'defabbrev fn)
                            "The body of this DEFABBREV form is a DECLARE ~
                             form, namely ~x0.  This is illegal and probably ~
                             is not what was intended."
                            (car (last body))))
                       (t
                        `(defmacro ,fn ,args
                           ,@doc-string-list
                           (list 'let
                                 (list ,@(defabbrev1 args))
                                 ,@(process-defabbrev-declares
                                    (butlast body 1))
                                 ',(car (last body))))))))))

; Essay on Evisceration

; We have designed the pretty printer so that it can print an
; "eviscerated" object, that is, an object that has had certain
; substructures removed.  We discuss the prettyprinter in the Essay on
; the ACL2 Prettyprinter.  The pretty printer has a flag, eviscp,
; which indicates whether the object has been eviscerated or not.  If
; not, then the full object is printed as it stands.  If so, then
; certain substructures of it are given special interpretation by the
; printer.  In particular, when the printer encounters a cons of the
; form (:evisceration-mark . x) then x is a string and the cons is
; printed by printing the characters in x (without the double
; gritches).

;     object                            pretty printed output
; (:evisceration-mark . "#")                     #
; (:evisceration-mark . "...")                   ...
; (:evisceration-mark . "<state>")               <state>
; (:evisceration-mark . ":EVISCERATION-MARK")    :EVISCERATION-MARK

; So suppose you have some object and you want to print it, implementing
; the CLTL conventions for *print-level* and *print-length*.  Then you
; must first scan it, inserting :evisceration-mark forms where
; appropriate.  But what if it contains some occurrences of
; :evisceration-mark?  Then you must use evisceration mechanism to print
; them correctly!  Once you have properly eviscerated the object, you can
; call the prettyprinter on it, telling it that the object has been
; eviscerated.  If, on the other hand, you don't want to eviscerate it,
; then you needn't sweep it to protect the native :evisceration-marks:
; just call the prettyprinter with the eviscp flag off.

(defconst *evisceration-mark* :evisceration-mark)

; Note: It is important that the evisceration-mark be a keyword.
; One reason is that (:evisceration-mark . ":EVISCERATION-MARK")
; couldn't be used to print a non-keyword because the package might
; need to be printed.  Another is that we exploit the fact that no
; event name nor any formal is *evisceration-mark*.  See
; print-ldd-full-or-sketch.  Furthermore, if the particular keyword
; chosen is changed, alter *anti-evisceration-mark* below!

(defconst *evisceration-hash-mark* (cons *evisceration-mark* "#"))
(defconst *evisceration-ellipsis-mark* (cons *evisceration-mark* "..."))
(defconst *evisceration-world-mark*
  (cons *evisceration-mark* "<world>"))
(defconst *evisceration-state-mark*
  (cons *evisceration-mark* "<state>"))
(defconst *evisceration-error-triple-marks*
  (list nil nil *evisceration-state-mark*))
(defconst *evisceration-hiding-mark*
  (cons *evisceration-mark* "<hidden>"))

(defconst *anti-evisceration-mark*
  (cons *evisceration-mark* ":EVISCERATION-MARK"))

(defmacro evisceratedp (eviscp x)
; Warning:  The value of x should be a consp.
  `(and ,eviscp (eq (car ,x) *evisceration-mark*)))

; Essay on Iprinting

; Through Version_3.4, when ACL2 eviscerated a form using a print-level or
; print-length from an evisc-tuple, the resulting # and ... made it impossible
; to read the form back in.  We have implemented "iprinting" (think
; "interactive printing") to deal with this problem.  Our implementation uses
; an "iprint array", or "iprint-ar" for short, as described below.  Now, when
; iprinting is enabled, then instead of # or ... we will see #@i# for i = 1, 2,
; etc.  See :doc set-iprint for more information at the user level.  In brief,
; the idea is to maintain a state global 'iprint-ar whose value is an ACL2
; array that associates each such i with its hidden value.  (This use of #@i#
; allows us also to think of "iprinting" as standing for "index printing" or "i
; printing".)

; We implement this idea by modifying the recursive subroutines of eviscerate
; to accumulate each association of a positive i with its hidden value. When
; fmt (or fms, etc.) is called, eviscerate-top or eviscerate-stobjs-top will be
; called in order to update the existing 'iprint-ar with those new
; associations.

; We use index 0 to store the most recent i for which #@i# has been printed,
; assuming iprinting is enabled, or else (list i) if iprinting is disabled.  We
; call such i the last-index, and it is initially 0.  Note that state global
; 'iprint-ar is thus always bound to an installed ACL2 array.

; When state global 'iprint-fal has a non-nil value (which is exactly when
; set-iprint was last called with a non-nil value of :share), it is a
; fast-alist that inverts iprint-ar in the following sense: for every pair (i
; . v) in iprint-ar with 1 <= i <= last-index, (v . i) is in the value of
; 'iprint-fal.  See :doc set-iprint for more about :share.

; We have to face a fundamental question: Do we use acons or aset1 as we
; encounter a new form to assign to some #@i# during those recursive
; subroutines?  The latter is dangerous in case we interrupt before installing
; the result in the state global.  So it's tempting to use acons -- but it
; could be inefficient to compress the iprint-ar on each top-level call.  So
; instead we use acons to build up a new alist from scratch.  Then at the
; top level, we apply aset1 for each entry if we can do so without needing to
; ``rollover'', i.e., set the last-index back to 0; otherwise we call compress1
; rather than making a series of aset1 calls.  With luck this final step will
; be fast and unlikely to be interrupted from the time the first aset1 or
; compress1 is applied until the state global 'iprint-ar is updated.

; Let's also comment on why we have a soft and a hard bound (as described in
; :doc set-iprint).  In general we allow indices to increase between successive
; top-level invocations, so that the user can read back in any forms that were
; printed. But the soft bound forces a rollover at the top level of LD when the
; last-index exceeds that bound, so that we don't hold on to a potentially
; unbounded amount of space for the objects in the iprint-ar. The hard bound
; (which generally exceeds the soft bound) steps in if the last-index exceeds
; it after pretty-printing a single form.  Thus, if there are large objects and
; very long runs between successive top-level forms, space can be
; reclaimed. The hard bound is therefore probably less likely to be of use.

; We maintain the invariant that the dimension of state global 'iprint-ar
; exceeds the hard bound.  Thus, when we update the 'iprint-ar in the normal
; case that the hard bound is not exceeded, then the dimension will not be
; exceeded either; that is, every update will be with an index that is in
; bounds.  In order to maintain this invariant, the hard bound is untouchable,
; and its setter function compresses the global iprint-ar with a new dimension
; that exceeds the specified hard bound.  Therefore the hard bound must be a
; number, not nil.  Notice that with this invariant, we can avoid compressing
; twice when we roll over upon exceeding the hard or soft bound: we first reset
; the last-index to 0 and then do the compression, rather than compressing once
; for the increased dimension and once for the rollover.

; We also maintain the invariant that the maximum-length of the 'iprint-ar is
; always at least four times its dimension.  See the comment about this in
; rollover-iprint-ar.

; It is tempting to cause an error when the user submits a form containing some
; #@j# and #@k# such that j <= last-index < k.  In such a case, k is from
; before the rollover and j is from after the rollover, so these couldn't have
; been stored during a prettyprint of the same form.  By default we avoid this
; restriction, because the user might want to read a list that includes some
; forms prettyprinted before the last rollover and other forms printed after
; the last rollover.  But if iprint sharing is on, then a subform that had been
; printed before rollover might include iprint indices that have since changed,
; which might be highly confusing.  So we make the above restriction on indices
; when iprint sharing is on, as documented in :doc set-iprint.

; We need to be sure that the global iprint-ar is installed as an ACL2 array, in
; order to avoid slow-array-warnings.  See the comment in
; push-wormhole-undo-formi for how we deal with this issue in the presence of
; wormholes.

; End of Essay on Iprinting

(defconst *sharp-atsign-ar* ; see get-sharp-atsign
  (let ((dim (1+ *iprint-hard-bound-default*)))
    (compress1
     'sharp-atsign-ar
     (cons `(:HEADER :DIMENSIONS     (,dim)
                     :MAXIMUM-LENGTH ,(1+ dim) ; no duplicates expected
                     :NAME           sharp-atsign-ar)
           (sharp-atsign-alist *iprint-hard-bound-default* nil)))))

(defun get-sharp-atsign (i)

; If i is below the hard bound, then we get the string #@i# from a fixed array,
; so that we don't have to keep consing up that string.

  (declare (xargs :guard (posp i)))
  (cond ((<= i *iprint-hard-bound-default*)
         (aref1 'sharp-atsign-ar *sharp-atsign-ar* i))
        (t (make-sharp-atsign i))))

(defun update-iprint-alist-fal (iprint-alist iprint-fal-new iprint-fal-old val)

; We are doing iprinting.  Iprint-alist is either a positive integer,
; representing the last-index but no accumulated iprint-alist, or else is a
; non-empty alist of entries (i . val_i).  See the Essay on Iprinting.

  (let ((pair (and iprint-fal-old
                   (or (hons-get val iprint-fal-new)
                       (hons-get val iprint-fal-old)))))
    (cond (pair
           (mv (cdr pair) iprint-alist iprint-fal-new))
          ((consp iprint-alist)
           (let ((index (1+ (caar iprint-alist))))
             (mv index
                 (acons index val iprint-alist)
                 (and iprint-fal-old
                      (hons-acons val index iprint-fal-new)))))
          (t
           (let ((index (1+ iprint-alist)))
             (mv index
                 (acons index val nil)
                 (and iprint-fal-old
                      (hons-acons val index iprint-fal-new))))))))

; We now define the most elementary eviscerator, the one that implements
; *print-level* and *print-length*.  In this same pass we also arrange to
; hide any object in alist, where alist pairs objects with their
; evisceration strings -- or if not a string, with the appropriate
; evisceration pair.

(mutual-recursion

(defun eviscerate1 (x v max-v max-n alist evisc-table hiding-cars
                      iprint-alist iprint-fal-new iprint-fal-old eager-p)

; Iprint-alist is either a symbol, indicating that we are not doing iprinting; a
; positive integer, representing the last-index but no accumulated iprint-alist;
; or an accumulated alist of entries (i . val_i).  See the Essay on Iprinting.
; Note that if iprint-alist is a symbol, then it is nil if no evisceration has
; been done based on print-length or print-level, else t.

; If iprint-fal-old is nil (i.e., if iprinting is off), then eager-p is
; essentially irrelevant; but as a sanity check, we insist that eager-p is nil
; in that case (as enforced by the assert$ call below).

  (let* ((temp (or (hons-assoc-equal x alist)
                   (hons-assoc-equal x evisc-table)))
         (eager-pair (and eager-p
                          (null (cdr temp))
                          (consp x)
                          (assert$
                           iprint-fal-old
                           (or (hons-get x iprint-fal-new)
                               (hons-get x iprint-fal-old))))))
    (cond ((cdr temp)
           (mv (cond ((stringp (cdr temp))
                      (cons *evisceration-mark* (cdr temp)))
                     (t (cdr temp)))
               iprint-alist
               iprint-fal-new))
          ((atom x)
           (mv (cond ((eq x *evisceration-mark*) *anti-evisceration-mark*)
                     (t x))
               iprint-alist
               iprint-fal-new))
          (eager-pair
           (mv (cons *evisceration-mark*
                     (get-sharp-atsign (cdr eager-pair)))
               iprint-alist
               iprint-fal-new))
          ((= v max-v)
           (cond ((symbolp iprint-alist)
                  (mv *evisceration-hash-mark* t iprint-fal-new))
                 (t
                  (mv-let (index iprint-alist iprint-fal-new)
                    (update-iprint-alist-fal iprint-alist
                                             iprint-fal-new
                                             iprint-fal-old
                                             x)
                    (mv (cons *evisceration-mark*
                              (get-sharp-atsign index))
                        iprint-alist
                        iprint-fal-new)))))
          ((member-eq (car x) hiding-cars)
           (mv *evisceration-hiding-mark* iprint-alist iprint-fal-new))
          (t (eviscerate1-lst x (1+ v) 0 max-v max-n alist evisc-table
                              hiding-cars iprint-alist
                              iprint-fal-new iprint-fal-old eager-p)))))

(defun eviscerate1-lst (lst v n max-v max-n alist evisc-table hiding-cars
                            iprint-alist iprint-fal-new iprint-fal-old eager-p)
  (let* ((temp (or (hons-assoc-equal lst alist)
                   (hons-assoc-equal lst evisc-table)))
         (eager-pair (and eager-p
                          (null (cdr temp))
                          (consp lst)
                          (assert$
                           iprint-fal-old
                           (or (hons-get lst iprint-fal-new)
                               (hons-get lst iprint-fal-old))))))
    (cond
     ((cdr temp)
      (mv (cond ((stringp (cdr temp))
                 (cons *evisceration-mark* (cdr temp)))
                (t (cdr temp)))
          iprint-alist
          iprint-fal-new))
     ((atom lst)
      (mv (cond ((eq lst *evisceration-mark*) *anti-evisceration-mark*)
                (t lst))
          iprint-alist
          iprint-fal-new))
     (eager-pair
      (mv (cons *evisceration-mark*
                (get-sharp-atsign (cdr eager-pair)))
          iprint-alist
          iprint-fal-new))
     ((= n max-n)
      (cond ((symbolp iprint-alist)
             (mv (list *evisceration-ellipsis-mark*) t iprint-fal-new))
            (t (mv-let (index iprint-alist iprint-fal-new)
                 (update-iprint-alist-fal iprint-alist
                                          iprint-fal-new
                                          iprint-fal-old
                                          lst)
                 (mv (cons *evisceration-mark*
                           (get-sharp-atsign index))
                     iprint-alist
                     iprint-fal-new)))))
     (t (mv-let (first iprint-alist iprint-fal-new)
          (eviscerate1 (car lst) v max-v max-n alist evisc-table
                       hiding-cars iprint-alist
                       iprint-fal-new iprint-fal-old eager-p)
          (mv-let (rest iprint-alist iprint-fal-new)
            (eviscerate1-lst (cdr lst) v (1+ n)
                             max-v max-n alist evisc-table
                             hiding-cars iprint-alist
                             iprint-fal-new iprint-fal-old eager-p)
            (mv (cons first rest) iprint-alist iprint-fal-new)))))))
)

(mutual-recursion

(defun eviscerate1p (x alist evisc-table hiding-cars)

; This function returns t iff (eviscerate1 x 0 -1 -1 alist evisc-table hidep)
; returns something other than x.  That is, iff the evisceration of x either
; uses alist, evisc-table, hiding or the *anti-evisceration-mark* (assuming
; that print-level and print-length never max out).

  (let ((temp (or (hons-assoc-equal x alist)
                  (hons-assoc-equal x evisc-table))))
    (cond ((cdr temp) t)
          ((atom x)
           (cond ((eq x *evisceration-mark*) t)
                 (t nil)))
          ((member-eq (car x) hiding-cars) t)
          (t (eviscerate1p-lst x alist evisc-table hiding-cars)))))

(defun eviscerate1p-lst (lst alist evisc-table hiding-cars)
  (let ((temp (or (hons-assoc-equal lst alist)
                  (hons-assoc-equal lst evisc-table))))
    (cond ((cdr temp) t)
          ((atom lst)
           (cond ((eq lst *evisceration-mark*) t)
                 (t nil)))
          (t (or (eviscerate1p (car lst) alist evisc-table hiding-cars)
                 (eviscerate1p-lst (cdr lst) alist evisc-table
                                   hiding-cars))))))
)

(defun eviscerate (x print-level print-length alist evisc-table hiding-cars
                     iprint-alist iprint-fal-new iprint-fal-old eager-p)

; See also eviscerate-top, which takes iprint-ar from the state and installs a
; new iprint-ar in the state, and update-iprint-alist, which describes the role
; of a non-symbol iprint-alist as per the Essay on Iprinting.

; Print-level and print-length should either be non-negative integers or nil.
; Alist and evisc-table are alists pairing arbitrary objects to strings or
; other objects.  Hiding-cars is a list of symbols.  Any x that starts with one
; of these symbols is printed as <hidden>.  If alist or evisc-table pairs an
; object with a string, the string is printed in place of the object.  If alist
; or evisc-table pairs an object with anything else, x, then x is substituted
; for the the object and is treated as eviscerated.  In general, alist will
; come from an evisceration tuple and evisc-table will be the value of the
; 'evisc-table table in the current ACL2 world.  We give priority to the former
; because the user may want to override the evisc-table, for example using ~P
; in a call of fmt.

; This function copies the structure x and replaces certain deep substructures
; with evisceration marks.  The determination of which substructures to so
; abbreviate is based on the same algorithm used to define *print-level* and
; *print-length* in CLTL, with the additional identification of all occurrences
; of any object in alist or evisc-table.

; For example, if x is '(if (member x y) (+ (car x) 3) '(foo . b)) and
; print-level is 2 and print-length is 3 then the output is:

; (IF (MEMBER X Y)
;     (+ (*evisceration-mark* . "#") 3)
;     (*evisceration-mark* . "..."))

; See pg 373 of CLTL.

; Of course we are supposed to print this as:

; (IF (MEMBER X Y) (+ # 3) ...)

; We consider a couple of special cases to reduce unnecessary consing
; of eviscerated values.

  (cond ((and (null print-level)
              (null print-length))

; Warning: Observe that even if alist is nil, x might contain the
; *evisceration-mark* or hiding expressions and hence have a
; non-trivial evisceration

         (cond ((eviscerate1p x alist evisc-table hiding-cars)
                (eviscerate1 x 0 -1 -1 alist evisc-table hiding-cars

; Since we are not eviscerating based on print-level or print-length, there is
; no involvement of iprinting, so we pass nil for the remaining arguments.

                             nil nil nil nil))
               (t (mv x iprint-alist iprint-fal-new))))
        (t (eviscerate1 (if eager-p (hons-copy x) x)
                        0
                        (or print-level -1)
                        (or print-length -1)
                        alist
                        evisc-table
                        hiding-cars
                        iprint-alist
                        iprint-fal-new
                        iprint-fal-old
                        eager-p))))

(defun eviscerate-simple (x print-level print-length alist evisc-table
                            hiding-cars)

; This wrapper for eviscerate avoids the need to pass back multiple values when
; the iprint-alist is nil and we don't care if evisceration has occurred.

  (mv-let (result null-iprint-alist null-iprint-fal)
    (eviscerate x print-level print-length alist evisc-table hiding-cars
                nil nil

; We normally pass in the current value of state global 'iprint-fal for the
; last argument, iprint-fal-old, of eviscerate.  However, since iprint-alist is
; nil, we know that it's fine to pass in nil for iprint-fal-old, and similarly
; for eager-p.

                nil nil)
    (assert$ (and (booleanp null-iprint-alist)
                  (null null-iprint-fal))
             result)))

(defun aset1-lst (name alist ar)
  (declare (xargs :guard (eqlable-alistp alist))) ; really nat-alistp
  (cond ((endp alist)
         ar)
        (t (aset1-lst name
                      (cdr alist)
                      (aset1 name ar (caar alist) (cdar alist))))))

; Next we define accessors for iprint arrays.

(defun iprint-hard-bound (state)
  (f-get-global 'iprint-hard-bound state))

(defun iprint-soft-bound (state)
  (f-get-global 'iprint-soft-bound state))

(defun iprint-last-index* (iprint-ar)
  (declare (xargs :guard (array1p 'iprint-ar iprint-ar)))
  (let ((x (aref1 'iprint-ar iprint-ar 0)))
    (if (consp x) ; iprinting is disabled
        (car x)
      x)))

(defun iprint-last-index (state)
  (iprint-last-index* (f-get-global 'iprint-ar state)))

(defun iprint-ar-illegal-index (index state)
  (declare (xargs :guard (and (natp index) (state-p state))))
  (or (zp index)
      (let* ((iprint-ar (f-get-global 'iprint-ar state))
             (bound (default 'iprint-ar iprint-ar)))
        (if (null bound)
            (> index (iprint-last-index* iprint-ar))
          (> index bound)))))

(defun iprint-enabledp (state)
  (natp (aref1 'iprint-ar (f-get-global 'iprint-ar state) 0)))

(defun iprint-ar-aref1 (index state)

; We do not try to determine if the index is appropriate, other than to avoid a
; guard violation on the aref1 call.  See the Essay on Iprinting.

  (declare (xargs :guard (and (posp index) (state-p state))))
  (let ((iprint-ar (f-get-global 'iprint-ar state)))

;; PAPER:
; We use a raw Lisp error since otherwise we get an error such as "Can't throw
; to tag RAW-EV-FNCALL".

    #-acl2-loop-only
    (cond ((>= index (car (dimensions 'iprint-ar iprint-ar)))

; The following error probably never occurs, since we have already done a
; bounds check with iprint-ar-illegal-index.

           (error
            "Out of range index for iprinting: ~s.~%See :DOC set-iprint."
            index)))
    (aref1 'iprint-ar iprint-ar index)))

(defun collect-posp-indices-to-header (ar acc)

; Accumulates the reverse of ar onto acc, skipping entries with index 0 and
; stopping just before the :header.

  (cond ((endp ar)
         (er hard 'collect-posp-indices-to-header
             "Implementation error: Failed to find :HEADER as expected!"))
        ((eq (caar ar) :HEADER)
         acc)
        (t
         (collect-posp-indices-to-header (cdr ar)
                                         (if (eql (caar ar) 0)
                                             acc
                                           (cons (car ar) acc))))))

(defun iprint-fal-name (iprint-fal)
  (if (consp iprint-fal)
      (cdr (last iprint-fal))
    iprint-fal))

(defun iprint-eager-p (iprint-fal)
  (eq (iprint-fal-name iprint-fal)
      :eager))

(defun init-iprint-fal (sym state)

; Warning: Consider also calling init-iprint-ar when calling this function.

; The initial value of state global 'iprint-fal is nil if we are not to re-use
; indices, and otherwise is the atom, :iprint-fal.  We choose a keyword so that
; fast-alist-summary can print that name nicely in any package.

  (declare (xargs :guard (symbolp sym)))
  (let* ((old-iprint-fal (f-get-global 'iprint-fal state))
         (old-iprint-name (iprint-fal-name old-iprint-fal))
         (new-iprint-fal (cond ((null sym) nil)
                               ((eq sym t)
                                :iprint-fal)
                               ((eq sym :same)
                                old-iprint-name)
                               (t sym))))
    (prog2$ (and (consp old-iprint-fal) ; optimization
                 (fast-alist-free old-iprint-fal))
            (pprogn (f-put-global 'iprint-fal new-iprint-fal state)
                    (mv (cond
                         ((eq old-iprint-name new-iprint-fal)
                          nil)
                         (new-iprint-fal
                          (msg "Iprinting is enabled with~@0 sharing, with a ~
                                fast-alist whose name is ~x1."
                               (if (iprint-eager-p new-iprint-fal)
                                   " eager"
                                 "")
                               new-iprint-fal))
                         (t
                          (msg "Iprinting is enabled without sharing.")))
                        state)))))

(defun rollover-iprint-ar (iprint-alist last-index state)

; We assume that iprinting is enabled.  Install a new iprint-ar, whose last
; index before rollover is intended to be last-index and whose alist is
; intended to extend state global 'iprint-ar, as the new (and compressed) value
; of state global 'iprint-ar.

  (let* ((old-iprint-ar (f-get-global 'iprint-ar state))
         (new-dim

; Clearly last-index exceeds the iprint-hard-bound, as required by one of our
; invariants (see the Essay on Iprinting), if we are rolling over because
; last-index exceeds that hard bound.  But we can also call rollover-iprint-ar
; when exceeding the soft bound, which may be smaller than the hard bound (it
; probably is smaller, typically).  The taking of this max is cheap so we
; always do it, so that rollover-iprint-ar will always preserve the above
; invariant.

; To illustrate the above point, evaluate the following forms in a fresh ACL2
; session and see the error if we bind new-dim to (1+ last-index).

; (set-ld-evisc-tuple (evisc-tuple 2 3 nil nil) state)
; (set-iprint t :soft-bound 2 :hard-bound 7)
; '((a b c d e) (a b c d e) (a b c d e))
; '((a b c d e) (a b c d e) (a b c d e) (a b c d e) (a b c d e))

          (1+ (max (iprint-hard-bound state) last-index)))
         (new-max-len

; A multiplier of 4 allows us to maintain the invariant that the maximum-length
; is always at least four times the dimension.  This guarantees that the
; 'iprint-ar alist never reaches the maximum-length because it never reaches
; 4*d, where d is the dimension, as this alist has at most:
; - up to d-2 values for index >= 1 since the latest rollover;
; - up to d-2 values for index >= 1 before the latest rollover;
; - at most two headers (the 2nd is just before a new compression at rollover)
; - no two successive bindings of index 0
; So without considering index 0, the maximum is (d-2 + d-2 + 2) = 2d-1.  Now
; for the bindings of index 0, double that and add one to get 4d-1.

; Thus, since the dimension never decreases (except when we reinitialize), we
; are assured that our use of aset1-lst in update-iprint-ar will never cause a
; recompression.  See also corresponding comments in disable-iprint-ar and
; enable-iprint-ar.

          (* 4 new-dim))
         (new-header
          (prog2$
           (or (<= new-max-len *maximum-positive-32-bit-integer*)
               (er hard 'rollover-iprint-ar
                   "Attempted to expand iprint-ar to a maximum-length of ~x0, ~
                    exceeding *maximum-positive-32-bit-integer*, which is ~x1."
                   new-max-len
                   *maximum-positive-32-bit-integer*))
           `(:HEADER :DIMENSIONS     (,new-dim)
                     :MAXIMUM-LENGTH ,new-max-len
                     :DEFAULT        ,last-index
                     :NAME           iprint-ar
                     :ORDER          :none)))
         (new-iprint-ar
          (compress1 'iprint-ar
                     (cons new-header
                           (acons 0 0
                                  (collect-posp-indices-to-header
                                   old-iprint-ar

; If we change the :order to < from :none, then we need to reverse iprint-alist
; just below.  But first read the comment in disable-iprint-ar to see why
; changing the :order from :none requires some thought.

                                   iprint-alist))))))
    (mv-let (msg state)
      (init-iprint-fal :same state)
      (declare (ignore msg))
      (f-put-global 'iprint-ar new-iprint-ar state))))

(defun update-iprint-fal-rec (iprint-fal-new iprint-fal-old)
  (cond ((atom iprint-fal-new) iprint-fal-old)
        (t (update-iprint-fal-rec (cdr iprint-fal-new)
                                  (hons-acons (caar iprint-fal-new)
                                              (cdar iprint-fal-new)
                                              iprint-fal-old)))))

(defun update-iprint-fal (iprint-fal-new state)
  (cond
   ((atom iprint-fal-new) state) ; optimization
   (t (f-put-global 'iprint-fal
                    (update-iprint-fal-rec iprint-fal-new
                                           (f-get-global 'iprint-fal state))
                    state))))

(defun update-iprint-ar-fal (iprint-alist iprint-fal-new iprint-fal-old state)

; We assume that iprinting is enabled.  Iprint-alist is known to be a consp.
; We update state globals 'iprint-ar and 'iprint-fal by updating them with the
; pairs in iprint-alist and iprint-fal-new, respectively.

  (let ((last-index (caar iprint-alist)))
    (cond ((> last-index (iprint-hard-bound state))

; We throw away iprint-fal-new, because we only want to re-use indices below
; last-index -- re-use of larger indices could quickly leave us pointing to
; stale values when re-printing (say, using without-evisc) recently-printed
; values.

           (rollover-iprint-ar iprint-alist last-index state))
          (t
           (assert$
            (or (null iprint-fal-old) ; might have passed in nil at top level
                (equal (f-get-global 'iprint-fal state)
                       iprint-fal-old))
            (pprogn
             (update-iprint-fal iprint-fal-new state)
             (f-put-global 'iprint-ar

; We know last-index <= (iprint-hard-bound state), and it is an invariant that
; this hard bound is less than the dimension of (@ iprint-ar).  See the
; discussion of this invariant in the Essay on Iprinting.  So last-index is
; less than that dimension, hence we can update with aset1 without encountering
; out-of-bounds indices.

                           (aset1-lst 'iprint-ar
                                      (acons 0 last-index iprint-alist)
                                      (f-get-global 'iprint-ar state))
                           state)))))))

(defun eviscerate-top (x print-level print-length alist evisc-table hiding-cars
                         state)

; We take iprint-ar from the state and then install a new iprint-ar in the state,
; in addition to returning the evisceration of x.  See eviscerate and the Essay
; on Iprinting for more details.

  (let ((iprint-fal-old (f-get-global 'iprint-fal state)))
    (mv-let (result iprint-alist iprint-fal-new)
      (eviscerate x print-level print-length alist evisc-table hiding-cars
                  (and (iprint-enabledp state)
                       (iprint-last-index state))
                  nil iprint-fal-old (iprint-eager-p iprint-fal-old))
      (fast-alist-free-on-exit
       iprint-fal-new
       (let ((state
              (cond
               ((eq iprint-alist t)
                (f-put-global 'evisc-hitp-without-iprint t state))
               ((atom iprint-alist) state)
               (t (update-iprint-ar-fal iprint-alist
                                        iprint-fal-new
                                        iprint-fal-old
                                        state)))))
         (mv result state))))))

; Essay on the ACL2 Prettyprinter

; The ACL2 prettyprinter is a two pass, linear time, exact prettyprinter.  By
; "exact" we mean that if it has a page of width w and a big enough form, it
; will guarantee to use all the columns, i.e., the widest line will end in
; column w.  The algorithm dates from about 1971 -- virtually the same code was
; in the earliest Edinburgh Pure Lisp Theorem Prover.  This approach to
; prettyprinting was invented by Bob Boyer; see
; http://www.cs.utexas.edu/~boyer/pretty-print.pdf.  Most prettyprinters are
; quadratic and inexact.

; The secret to this method is to make two linear passes, ppr1 and ppr2.  The
; first pass builds a data structure, called a ``ppr tuple,'' that tells the
; second pass how to print.

; Some additional general principles of our prettyprinter are
; (i)    Print flat whenever possible.

; (ii)   However, don't print flat argument lists of length over 40; they're
;        too hard to parse.  (But this can be overridden by state global
;        ppr-flat-right-margin.)

; (iii)  Atoms and eviscerated things (which print like atoms, e.g., `<world>')
;        may be printed on a single line.

; (iv)   But parenthesized expressions should not be printed on a line with any
;        other argument (unless the whole form fits on the line).  Thus we may
;        produce:
;        `(foo (bar a) b c d)'
;        and
;        `(foo a b
;              c d)'
;        But we never produce
;        `(foo (bar a) b
;              c d)'
;        preferring instead
;        `(foo (bar a)
;              b c d)'
;        It is our belief that parenthesized expressions are hard to parse and
;        after doing so the eye tends to miss little atoms (like b above)
;        hiding in their shadows.

; To play with ppr we recommend executing this form:

; (ppr2 (ppr1 x (print-base) (print-radix) 30 0 state t)
;       0 *standard-co* state t)

; This will prettyprint x on a page of width 30, assuming that printing starts
; in column 0.  To see the ppr tuple that drives the printer, just evaluate the
; inner ppr1 form,
; (ppr1 x (print-base) (print-radix) 30 0 state nil).

; The following test macro is handy.  A typical call of the macro is

; (test 15 (foo (bar x) (mum :key1 val1 :key2 :val2)))

; Note that x is not evaluated.  If you want to evaluate x and ppr the value,
; use

;   (testfn 10
;           (eviscerate-simple `(foo (bar x)
;                             (mum :key1 :val1 :key2 :val2)
;                             ',(w state))
;                       nil nil ; print-level and print-length
;                       (world-evisceration-alist state nil)
;                       nil
;                       nil)
;           state)

; Note that x may be eviscerated, i.e., eviscerated objects in x are printed in
; their short form, not literally.

;   (defun testfn (d x state)
;     (declare (xargs :mode :program :stobjs (state)))
;     (let ((tuple (ppr1 x (print-base) (print-radix) d 0 state t)))
;       (pprogn
;        (fms "~%Tuple: ~x0~%Output:~%" (list (cons #\0 tuple))
;             *standard-co* state nil)
;        (ppr2 tuple 0 *standard-co* state t)
;        (fms "~%" nil *standard-co* state nil))))
;
;   (defmacro test (d x)

; Ppr tuples record enough information about the widths of various forms so
; that it can be computed without having to recompute any part of it and so
; that the second pass can print without having to count characters.

; A ppr tuple has the form (token n . z).  In the display below, the variables
; ti represent ppr tuples and the variables xi represent objects to be printed
; directly.  Any xi could an eviscerated object, a list whose car is the
; evisceration mark.

; (FLAT n x1 ... xk) - Print the xi, separated by spaces, all on one
;                      line. The total width of output will be n.
;                      Note that k >= 1.  Note also that such a FLAT
;                      represents k objects.  A special case is (FLAT
;                      n x1), which represents one object.  We make
;                      this observation because sometimes (in
;                      cons-ppr1) we `just know' that k=1 and the
;                      reason is: we know the FLAT we're holding
;                      represents a single object.

; (FLAT n x1... . xk)- Print the xi, separated by spaces, with xk
;                      separated by `. ', all on one line.  Here xk
;                      is at atom or an eviscerated object.

; (FLAT n . xk)      - Here, xk is an atom (or an eviscerated object).
;                      Print a dot, a space, and xk.  The width will
;                      be n.  Note that this FLAT does not actually
;                      represent an object.  That is, no Lisp object
;                      prints as `. xk'.

; Note: All three forms of FLAT are really just (FLAT n . x) where x is a
; possibly improper list and the elements of x (and its final cdr) are printed,
; separated appropriately by spaces or dot.

; (MATCHED-KEYWORD n x1)
;                    - Exactly like (FLAT n x1), i.e., prints x1,
;                      but by virtue of being different from FLAT
;                      no other xi's are ever added.  In this tuple,
;                      x1 is always a keyword and it will appear on
;                      a line by itself.  Its associated value will
;                      appear below it in the column because we tried
;                      to put them on the same line but we did not have
;                      room.

; (DOT 1)            - Print a dot.

; (QUOTE n . t1)     - Print a single-quote followed by pretty-
;                      printing the ppr tuple t1.

; (WIDE n t1 t2 ...) - Here, t1 is a FLAT tuple of width j.  We
;                      print an open paren, the contents of t1, a
;                      space, and then we prettyprint each of the
;                      remaining ti in a column.  When we're done, we
;                      print a close paren.  The width of the longest
;                      line we will print is n.

; (i n t1 ...)       - We print an open paren, prettyprint t1, then
;                      do a newline.  Then we prettyprint the
;                      remaining ti in the column that is i to the
;                      right of the paren.  We conclude with a close
;                      paren.  The width of the longest line we will
;                      print is n.  We call this an `indent tuple'.

; (KEYPAIR n t1 . t2)- Here, t1 is a FLAT tuple of width j.  We print
;                      t1, a space, and then prettyprint t2.  The
;                      length of the longest line we will print is n.

; The sentences "The length of the longest line we will print is n."
; bears explanation.  Consider

; (FOO (BAR X)
;      (MUMBLE Y)
;      Z)
;|<- 15 chars  ->|
; 123456789012345

; The length of the longest line, n, is 15.  That is, the length of the longest
; line counts the spaces from the start of the printing.  In the case of a
; KEYPAIR tuple:

; :KEY (FOO
;       (BAR X)
;       Y)
;|<- 13      ->|

; we count the spaces from the beginning of the keyword.  That is, we consider
; the whole block of text.

; Below we print test-term in two different widths, and display the ppr tuple
; that drives each of the two printings.

; (assign test-term
;         '(FFF (GGG (HHH (QUOTE (A . B))))
;               (III YYY ZZZ)))
;
;
; (ppr2 (ppr1 (@ test-term) (print-base) (print-radix) 30 0 state nil) 0
;       *standard-co* state nil)
; ; =>
; (FFF (GGG (HHH '(A . B)))          (WIDE 25 (FLAT 3 FFF)
;      (III YYY ZZZ))                         (FLAT 20 (GGG (HHH '(A . B))))
;                                             (FLAT 14 (III YYY ZZZ)))
; <-          25         ->|
;
; (ppr2 (ppr1 (@ test-term) (print-base) (print-radix) 20 0 state nil) 0
;       *standard-co* state nil)
; ; =>
; (FFF                               (1 20 (FLAT 3 FFF)
;  (GGG                                    (4 19 (FLAT 3 GGG)
;      (HHH '(A . B)))                           (FLAT 15 (HHH '(A . B))))
;  (III YYY ZZZ))                          (FLAT 14 (III YYY ZZZ)))
;
; <-       20       ->|

; The function cons-ppr1, below, is the first interesting function in the nest.
; We want to build a tuple to print a given list form, like a function call.
; We basically get the tuple for the car and a list of tuples for the cdr and
; then use cons-ppr1 to combine them.  The resulting list of tuples will be
; embedded in either a WIDE or an indent tuple.  Thus, this list of tuples we
; will create describes a column of forms.  The number of items in that column
; is not necessarily the same as the number of arguments of the function call.
; For example, the term (f a b c) might be prettyprinted as
; (f a
;    b c)
; where b and c are printed flat on a single line.  Thus, the three arguments
; of f end up being described by a list of two tuples, one for a and another
; for b and c.

; To form lists of tuples we just use cons-ppr1 to combine the tuples we get
; for each element.

; Let x and lst be, respectively, a ppr tuple for an element and a list of
; tuples for list of elements.  Think of lst as describing a column of forms.
; Either x can become another item that column, or else x can be incorporated
; into the first item in that column.  For example, suppose x will print as X
; and lst will print as a column containing y1, y2, etc.  Then we have this
; choice for printing x and lst:

; lengthened column          lengthened first row
; x                          x y1
; y1                         y2
; ...                        ...

; We get the `lengthened column' behavior if we just cons x onto lst.  We get
; the `lengthened row' behavior if we merge the tuples for x and y1.  But we
; only merge if they both print flat.

; Now we lay down some macros that help with the efficiency of the FMT
; functions, by making it easy to declare various formals and function values
; to be fixnums.  See the Essay on Fixnum Declarations.

(defmacro mv-letc (vars form body)
  `(mv-let ,vars ,form
           (declare (type (signed-byte 30) col))
           ,body))

(defmacro er-hard-val (val &rest args)

; Use (er-hard-val val ctx str ...) instead of (er hard? ctx str ...)
; when there is an expectation on the return type, which should be the
; type of val.  Compilation with the cmulisp compiler produces many
; warnings if we do not use some such device.

  `(prog2$ (er hard? ,@args)
           ,val))

(defmacro er-hard?-val? (val quiet &rest args)

; We use er-hard?-val to signal an error unless quiet is true,

  `(if ,quiet
       ,val
     (er-hard-val ,val ,@args)))

(defmacro the-fixnum! (n ctx)

; See also the-half-fixnum!.

  (let ((upper-bound (fixnum-bound)))
    (declare (type (signed-byte 30) upper-bound))
    (let ((lower-bound (- (1+ upper-bound))))
      (declare (type (signed-byte 30) lower-bound))
      `(the-fixnum
        (let ((n ,n))
          (if (and (<= n ,upper-bound)
                   (>= n ,lower-bound))
              n
            (er-hard-val 0 ,ctx
                         "The object ~x0 is not a fixnum ~
                          (precisely:  not a (signed-byte 30))."
                         n)))))))

(defmacro the-half-fixnum! (n ctx)

; Same as the-fixnum!, but leaves some room.

  (let ((upper-bound (floor (fixnum-bound) 2))) ; (1- (expt 2 28))
    (declare (type (signed-byte 29) upper-bound))
    (let ((lower-bound (- (1+ upper-bound))))
      (declare (type (signed-byte 29) lower-bound))
      `(the-fixnum
        (let ((n ,n))
          (if (and (<= n ,upper-bound)
                   (>= n ,lower-bound))
              n
            (er-hard-val 0 ,ctx
                         "The object ~x0 is not a `half-fixnum' ~
                          (precisely:  not a (signed-byte 29))."
                         n)))))))

(defmacro the-unsigned-byte! (bits n ctx)
  `(the (unsigned-byte ,bits)
        (let ((n ,n) (bits ,bits))
          (if (unsigned-byte-p bits n)
              n
            (er-hard-val 0 ,ctx
                         "The object ~x0 is not an (unsigned-byte ~x1)."
                         n bits)))))

(defmacro the-string! (s ctx)
  `(if (stringp ,s)
       (the string ,s)
     (er-hard-val "" ,ctx
                  "Not a string:  ~x0."
                  ,s)))

(defun xxxjoin-fixnum (fn args root)

; This is rather like xxxjoin, but we wrap the-fixnum around all
; arguments.

  (declare (xargs :guard (true-listp args)))
  (if (cdr args)
      (list 'the-fixnum
            (list fn
                  (list 'the-fixnum (car args))
                  (xxxjoin-fixnum fn (cdr args) root)))
    (if args ; one arg
        (list 'the-fixnum (car args))
      root)))

(defmacro +f (&rest args)
  (xxxjoin-fixnum '+ args 0))

(defmacro -f (arg1 &optional arg2)
  (if arg2
      `(the-fixnum (- (the-fixnum ,arg1)
                      (the-fixnum ,arg2)))
    `(the-fixnum (- (the-fixnum ,arg1)))))

(defmacro 1-f (x)
  (list 'the-fixnum
        (list '1- (list 'the-fixnum x))))

(defmacro 1+f (x)
  (list 'the-fixnum
        (list '1+ (list 'the-fixnum x))))

(defmacro charf (s i)
  (list 'the 'character
        (list 'char s i)))

(defmacro *f (&rest args)
  (xxxjoin-fixnum '* args 1))

; Essay on the Printing of Dotted Pairs and

; It is instructive to realize that we print a dotted pair as though it were a
; list of length 3 and the dot was just a normal argument.

; In the little table below I show, for various values of d, two things: the
; characters output by

; (ppr2 (ppr1 `(xx . yy) (print-base) (print-radix) d 0 state nil)
;       0 *standard-co* state nil)

; and the ppr tuple produced by the ppr1 call.
;
; d         output                 ppr tuple

;        |<-  9  ->|

; 9       (XX . YY)              (FLAT 9 (XX . YY))

; 8       (XX                    (3 8 (FLAT 2 XX) (FLAT 5 . YY))
;            . YY)

; 7       (XX                    (2 7 (FLAT 2 XX) (FLAT 5 . YY))
;           . YY)

; 6       (XX                    (1 6 (FLAT 2 XX) (FLAT 5 . YY))
;          . YY)

; 5       (XX                    (2 5 (FLAT 2 XX) (DOT 1) (FLAT 3 YY))
;           .
;           YY)

; 4       (XX                    (1 4 (FLAT 2 XX) (DOT 1) (FLAT 3 YY))
;          .
;          YY)

; The fact that the dot is not necessarily connected to (on the same line as)
; the atom following it is the reason we have the (DOT 1) tuple.  We have to
; represent the dot so that its placement is first class.  So when we're
; assembling the tuple for a list, we cdr down the list using cons-ppr1 to put
; together the tuple for the car with the tuple for the cdr.  If we reach a
; non-nil cdr, atm, we call cons-ppr1 on the dot tuple and the tuple
; representing the atm.  Depending on the width we have, this may produce (FLAT
; n . atm) which attaches the dot to the atm, or ((DOT 1) (FLAT n atm)) which
; leaves the dot on a line by itself.

; We want keywords to appear on new lines.  That means if the first element of
; lst is a keyword, don't merge (unless x is one too).

; BUG
; ACL2 p!>(let ((x '(foo bigggggggggggggggg . :littlllllllllllllle)))
;          (ppr2 (ppr1 x (print-base) (print-radix) 40 0 state nil)
;                0 *standard-co* state nil))
; (x   = (DOT 1)
; lst = ((FLAT 21 :LITTLLLLLLLLLLLLLLE))
; val = ((FLAT 23 . :LITTLLLLLLLLLLLLLLE)))
;
; HARD ACL2 ERROR in CONS-PPR1:  I thought I could force it!

(defmacro ppr-flat-right-margin ()
  '(f-get-global 'ppr-flat-right-margin state))

(defun set-ppr-flat-right-margin (val state)
  (if (posp val)
      (f-put-global 'ppr-flat-right-margin val state)
    (prog2$ (illegal 'set-ppr-flat-right-margin
                     "Set-ppr-flat-right-margin takes a positive integer ~
                      argument, unlike ~x0."
                     (list (cons #\0 val)))
            state)))

; Note: In the function below, column is NOT a number!  Often in this code,
; ``col'' is used to represent the position of the character column into which
; we are printing.  But ``column'' is a list of ppr tuples.

(defun keyword-param-valuep (tuple eviscp)

; We return t iff tuple represents a single object that could plausibly be the
; value of a keyword parameter.  The (or i ii iii iv) below checks that tuple
; represents a single object, either by being (i) a FLAT tuple listing exactly
; one object (ii) a QUOTE tuple, (iii) a WIDE tuple, or (iv) an indent tuple.
; The only other kinds of tuples are KEYPAIR tuples, FLAT tuples representing
; dotted objects `. atm', FLAT tuples representing several objects `a b c', and
; MATCHED-KEYWORD tuples representing keywords whose associated values are on
; the next line.  These wouldn't be provided as the value of a keyword
; argument.

  (or (and (eq (car tuple) 'flat)
           (not (or (atom (cddr tuple)) ; tuple is `. atm'
                    (evisceratedp eviscp (cddr tuple))))
           (null (cdr (cddr tuple))))
      (eq (car tuple) 'quote)
      (eq (car tuple) 'wide)
      (integerp (car tuple))))

(defun cons-ppr1 (x column width ppr-flat-right-margin eviscp)

; Here, x is a ppr tuple representing either a dot or a single object and
; column is a list of tuples corresponding to a list of objects (possibly a
; list of length greater than that of column).  Intuitively, column will print
; as a column of objects and we want to add x to that column, either by
; extending the top row or adding a new row.  In the most typical case, x might
; be (FLAT 3 ABC) and column is ((FLAT 7 DEF GHI) (...)).  Thus our choices
; would be to produce

; lengthened column          lengthened first row
; ABC                        ABC DEF GHI
; DEF GHI                    (...)
; (...)

; It is also here that we deal specially with keywords.  If x is
; (FLAT 3 :ABC) and column is ((...) (...)) then we have the choice:

; lengthened column          lengthened first row
; :ABC                       :ABC (...)
; (...)                      (...)
; (...)

; The default behavior is always to lengthen the column, which is just to cons
; x onto column.

  (cond
   ((and (eq (car x) 'flat)

; Note: Since x represents a dot or an object, we know that it is not of the
; form (FLAT n . atm).  Thus, (cddr x) is a list of length 1 containing a
; single (possibly eviscerated) object, x1.  If that object is an atom (or
; prints like one) we'll consider merging it with whatever else is on the first
; row.

         (or (atom (car (cddr x)))
             (evisceratedp eviscp (car (cddr x))))
         (consp column))

    (let ((x1 (car (cddr x)))
          (row1 (car column)))

; We know x represents the atom x1 (actually, x1 may be an eviscerated object,
; but if so it prints flat like an atom, e.g., `<world>').  Furthermore, we
; know column is non-empty and so has a first element, e.g., row1.

      (cond
       ((keywordp x1)

; So x1 is a keyword.  Are we looking at a keypair?  We are if row1 represents
; a single value.  By a ``single value'' we mean a single object that can be
; taken as the value of the keyword x1.  If row1 represents a sequence of more
; than one object, e.g., (FLAT 5 a b c), then we are not in a keypair situation
; because keyword argument lists must be keyword/value pairs all the way down
; and we form these columns bottom up, so if b were a keyword in the proper
; context, we would have paired it with c as keypair, not merged it, or we
; would have put it in a MATCHED-KEYWORD, indicating that its associated value
; is below it in the column.  If row1 does not represent a single value we act
; just like x1 had not been a keyword, i.e., we try to merge it with row1.
; This will shut down subsequent attempts to create keypairs above us.

        (cond
         ((and (keyword-param-valuep row1 eviscp)
               (or (null (cdr column))
                   (eq (car (cadr column)) 'keypair)
                   (eq (car (cadr column)) 'matched-keyword)))

; So x1 is a keyword, row1 represents a keyword parameter value, and
; the rest of the column represents keyword/value pairs.  The last
; test is made by just checking the item on the column below row1.  It
; would only be a keyword/value pair if the whole column consisted of
; those.  We consider making a keypair of width n = width of key, plus
; space, plus width of widest line in row1.  Note that we don't mind
; this running over the standard 40 character max line length because
; it is so iconic.

          (let ((n (+ (cadr x) (+ 1 (cadr row1)))))
            (cond ((<= n width)
                   (cons
                    (cons 'keypair (cons n (cons x row1)))
                    (cdr column)))

; Otherwise, we put x on a newline and leave the column as it was.  Note that
; we convert x from a FLAT to a MATCHED-KEYWORD, to ensure that it stays on a
; line by itself and to ensure keyword/value pairs encountered above us in the
; bottom-up processing to be paired with KEYPAIR.

                  (t (cons (cons 'MATCHED-KEYWORD (cdr x))
                           column)))))

; In this case, we are not in the context of a keyword/value argument even
; though x is a keyword.  So we act just like x is not a keyword and see
; whether we can merge it with row1.  We merge only if row1 is FLAT already and
; the width of the merged row is acceptable.  Even if row1 prints as `. atm' we
; will merge, giving rise to such displays as

; (foo a b c
;      d e f . atm)

         ((eq (car row1) 'flat)
          (let ((n (+ (cadr x) (+ 1 (cadr row1)))))
            (cond ((and (<= n ppr-flat-right-margin) (<= n width))
                   (cons
                    (cons 'flat (cons n (cons x1 (cddr row1))))
                    (cdr column)))
                  (t (cons x column)))))
         (t (cons x column))))

; In this case, x1 is not a keyword.  But it is known to print in atom-like
; way, e.g., `ABC' or `<world>'.  So we try a simple merge following the same
; scheme as above.

       ((eq (car row1) 'flat)
        (let ((n (+ (cadr x) (+ 1 (cadr row1)))))
          (cond ((and (<= n ppr-flat-right-margin) (<= n width))
                 (cons
                  (cons 'flat (cons n (cons x1 (cddr row1))))
                  (cdr column)))
                (t (cons x column)))))
       (t (cons x column)))))
   ((and (eq (car x) 'dot)
         (consp column))
    (let ((row1 (car column)))
      (cond ((eq (car row1) 'flat)

; In this case we know (car (cddr row1)) is an atom (or an eviscerated object)
; and it becomes the cddr of the car of the answer, which puts the dot on the
; same line as the terminal cdr.

             (let ((n (+ (cadr x) (+ 1 (cadr row1)))))
               (cond ((and (<= n ppr-flat-right-margin) (<= n width))
                      (cons
                       (cons 'flat
                             (cons n (car (cddr row1))))
                       (cdr column)))
                     (t (cons x column)))))
            (t (cons x column)))))

; In this case, x1 does not print flat.  So we add a new row.

   (t (cons x column))))

(defun flsz-integer (x print-base acc)
  (declare (type (unsigned-byte 5) print-base)
           (type (signed-byte 30) acc)
           (xargs :guard (print-base-p print-base)))
  (the-fixnum
   (cond ((< x 0)
          (flsz-integer (- x) print-base (1+f acc)))
         ((< x print-base) (1+f acc))
         (t (flsz-integer (truncate x print-base) print-base (1+f acc))))))

(defun flsz-atom (x print-base print-radix acc state)
  (declare (type (unsigned-byte 5) print-base)
           (type (signed-byte 30) acc))
  (the-fixnum
   (cond ((> acc (the (signed-byte 30) 100000))

; In order to make it very simple to guarantee that flsz and flsz-atom return
; fixnums, we ensure that acc is small enough below.  We could certainly
; provide a much more generous bound, but 100,000 seems safe at the moment!

          100000)
         ((integerp x)
          (flsz-integer x
                        print-base
                        (cond ((null print-radix)
                               acc)
                              ((int= print-base 10) ; `.' suffix
                               (+f 1 acc))
                              (t ; #b, #o, or #x prefix
                               (+f 2 acc)))))
         ((symbolp x)

; For symbols we add together the length of the "package part" and the symbol
; name part.  We include the colons in the package part.

          (+f (cond
               ((keywordp x) (1+f acc))
               ((symbol-in-current-package-p x state)
                acc)
               (t
                (let ((p (symbol-package-name x)))
                  (cond ((needs-slashes p state)
                         (+f 4 acc (the-half-fixnum! (length p)
                                                     'flsz-atom)))
                        (t (+f 2 acc (the-half-fixnum! (length p)
                                                       'flsz-atom)))))))
              (let ((s (symbol-name x)))
                 (cond ((needs-slashes s state)
                        (+f 2 (the-half-fixnum! (length s) 'flsz-atom)))
                       (t (+f (the-half-fixnum! (length s) 'flsz-atom)))))))
         ((rationalp x)
          (flsz-integer (numerator x)
                        print-base
                        (flsz-integer (denominator x)
                                      print-base
                                      (cond ((null print-radix)
                                             (+f 1 acc))
                                            ((int= print-base 10) ; #10r prefix
                                             (+f 5 acc))
                                            (t ; #b, #o, or #x prefix
                                             (+f 3 acc))))))
         ((complex-rationalp x)
          (flsz-atom (realpart x)
                     print-base
                     print-radix
                     (flsz-atom (imagpart x) print-base print-radix acc state)
                     state))
         ((stringp x)
          (+f 2 acc (the-half-fixnum! (length x) 'flsz-atom)))
         ((characterp x)
          (+f acc
              (cond ((eql x #\Newline) 9)
                    ((eql x #\Rubout) 8)
                    ((eql x #\Return) 8)
                    ((eql x #\Space) 7)
                    ((eql x #\Page) 6)
                    ((eql x #\Tab) 5)
                    (t 3))))
         (t 0))))

(defconst *newline-string*
  (string #\Newline))

(defun flsz1 (x print-base print-radix j maximum state eviscp)

; Actually, maximum should be of type (signed-byte 29).

  (declare (type (unsigned-byte 5) print-base)
           (type (signed-byte 30) j maximum))
  (the-fixnum
   (cond ((> j maximum) j)
         ((atom x) (flsz-atom x print-base print-radix j state))
         ((evisceratedp eviscp x)
          (let ((p (search *newline-string* (cdr x) :from-end t)))
            (cond (p (1+ maximum)) ; pretending width is exceeded
                  (t (+f j (the-half-fixnum! (length (cdr x)) 'flsz))))))
         ((atom (cdr x))
          (cond ((null (cdr x))
                 (flsz1 (car x) print-base print-radix (+f 2 j) maximum state
                        eviscp))
                (t (flsz1 (cdr x)
                          print-base
                          print-radix
                          (flsz1 (car x) print-base print-radix (+f 5 j)
                                 maximum state eviscp)
                          maximum state eviscp))))
         ((and (eq (car x) 'quote)
               (consp (cdr x))
               (null (cddr x)))
          (flsz1 (cadr x) print-base print-radix (+f 1 j) maximum state
                 eviscp))
         (t (flsz1 (cdr x)
                   print-base
                   print-radix
                   (flsz1 (car x) print-base print-radix (+f 1 j) maximum state
                          eviscp)
                   maximum state eviscp)))))

#+acl2-infix
(defun output-in-infixp (state)
  (let ((infixp (f-get-global 'infixp state)))
    (or (eq infixp t) (eq infixp :out))))

#+acl2-infix
(defun flatsize-infix (x print-base print-radix termp j max state eviscp)

; Suppose that printing x flat in infix notation causes k characters to come
; out.  Then we return j+k.  All answers greater than max are equivalent.

; If you think of j as the column into which you start printing flat, then this
; returns the column you'll print into after printing x.  If that column
; exceeds max, which is the right margin, then it doesn't matter by how far it
; exceeds max.

; In our $ infix notation, flat output has two extra chars in it, the $ and
; space.  But note that we use infix output only if infixp is t or :out.

  (declare (ignore termp))
  (+ 2 (flsz1 x print-base print-radix j max state eviscp)))

(defun flsz (x termp j maximum state eviscp)
  #-acl2-infix (declare (ignore termp))
  (declare (type (signed-byte 30) j maximum))
  (cond #+acl2-infix
        ((output-in-infixp state)
         (flatsize-infix x (print-base) (print-radix) termp j maximum state
                         eviscp))
        (t (flsz1 x
                  (the-fixnum (print-base))
                  (print-radix)
                  j maximum state eviscp))))

(defun max-width (lst maximum)
  (cond ((null lst) maximum)
        ((> (cadr (car lst)) maximum)
         (max-width (cdr lst) (cadr (car lst))))
        (t (max-width (cdr lst) maximum))))

(mutual-recursion

(defun ppr1 (x print-base print-radix width rpc state eviscp)

; We create a ppr tuple for x, i.e., a list structure that tells us how to
; prettyprint x, in a column of the given width.  Rpc stands for `right paren
; count' and is the number of right parens that will follow the printed version
; of x.  For example, in printing the x in (f (g (h x)) u) there will always be
; 2 right parens after it.  So we cannot let x use the entire available width,
; only the width-2.  Rpc would be 2.  Eviscp indicates whether we are to think
; of evisc marks as printing as atom-like strings or whether they're just
; themselves as data.

  (declare (type (signed-byte 30) print-base width rpc))
  (let ((sz (flsz1 x print-base print-radix rpc width state eviscp)))
    (declare (type (signed-byte 30) sz))
    (cond ((or (atom x)
               (evisceratedp eviscp x)
               (and (<= sz width)
                    (<= sz (ppr-flat-right-margin))))
           (cons 'flat (cons sz (list x))))
          ((and (eq (car x) 'quote)
                (consp (cdr x))
                (null (cddr x)))
           (let* ((x1 (ppr1 (cadr x) print-base print-radix (+f width -1) rpc state
                            eviscp)))
             (cons 'quote (cons (+ 1 (cadr x1)) x1))))
          (t
           (let* ((x1 (ppr1 (car x) print-base print-radix (+f width -1)
                            (the-fixnum (if (null (cdr x)) (+ rpc 1) 0))
                            state eviscp))

; If the fn is a symbol (or eviscerated, which we treat as a symbol), then the
; hd-sz is the length of the symbol.  Else, hd-sz is nil.  Think of (null
; hd-sz) as meaning "fn is a lambda expression".

                  (hd-sz (cond ((or (atom (car x))
                                    (evisceratedp eviscp (car x)))
                                (cadr x1))
                               (t nil)))

; When printing the cdr of x, give each argument the full width (minus 1 for
; the minimal amount of indenting).  Note that x2 contains the ppr tuples for
; the car and the cdr.

                  (x2 (cons x1
                            (ppr1-lst (cdr x) print-base print-radix (+f width -1)
                                      (+f rpc 1) state eviscp)))

; If the fn is a symbol, then we get the maximum width of any single argument.
; Otherwise, we get the maximum width of the fn and its arguments.

                  (maximum (cond (hd-sz (max-width (cdr x2) -1))
                                 (t (max-width x2 -1)))))

             (cond ((null hd-sz)

; If the fn is lambda, we indent the args by 1 and report the width of the
; whole to be one more than the maximum computed above.

                    (cons 1 (cons (+ 1 maximum) x2)))
                   ((<= (+ hd-sz (+ 2 maximum)) width)

; We can print WIDE if we have room for an open paren, the fn, a space, and the
; widest argument.

                    (cons 'wide
                          (cons (+ hd-sz (+ 2 maximum)) x2)))
                   ((< maximum width)

; If the maximum is less than the width, we can do exact indenting of the
; arguments to make the widest argument come out on the right margin.  This
; exactness property is one of the things that makes this algorithm produce
; such beautiful output: we get the largest possible indentation, which makes
; it easy to identify peer arguments.  How much do we indent?  width-maximum
; will guarantee that the widest argument ends on the right margin.  However,
; we believe that it is more pleasing if argument columns occur at regular
; indents.  So we limit our indenting to 5 and just give up the white space
; over on the right margin.  Note that we compute the width of the whole term
; accordingly.

                    (cons (min 5 (+ width (- maximum)))
                          (cons (+ maximum (min 5 (+ width (- maximum))))
                                x2)))

; If maximum is not less than width, we indent by 1.

                   (t (cons 1 (cons (+ 1 maximum) x2)))))))))


; The next function computes a ppr tuple for each element of lst.  Typically
; these are all arguments to a function.  But of course, we prettyprint
; arbitrary constants and so have to handle the case that the list is not a
; true-list.

; If you haven't read about cons-ppr1, above, do so now.

(defun ppr1-lst (lst print-base print-radix width rpc state eviscp)

  (declare (type (signed-byte 30) print-base width rpc))
  (cond ((atom lst)

; If the list is empty and null, then nothing is printed (besides the parens
; which are being accounted for otherwise).  If the list is terminated by some
; non-nil atom, we will print a dot and the atom.  We do that by merging a dot
; tuple into the flat for the atom, if there's room on the line, using
; cons-ppr1.  Where this merged flat will go, i.e., will it be indented under
; the car as happens in the Essay on the Printing of Dotted Pairs, is the
; concern of ppr1-lst, not the cons-ppr1.  The cons-ppr1 below just produces a
; merged flat containing the dot, if the width permits.

         (cond ((null lst) nil)
               (t (cons-ppr1 '(dot 1)
                             (list (ppr1 lst print-base print-radix width rpc
                                         state eviscp))
                             width (ppr-flat-right-margin) eviscp))))

; The case for an eviscerated terminal cdr is handled the same way.

        ((evisceratedp eviscp lst)
         (cons-ppr1 '(dot 1)
                    (list (ppr1 lst print-base print-radix width rpc state
                                eviscp))
                    width (ppr-flat-right-margin) eviscp))

; If the list is a true singleton, we just use ppr1 and we pass it the rpc that
; was passed in because this last item will be followed by that many parens on
; the same line.

        ((null (cdr lst))
         (list (ppr1 (car lst) print-base print-radix width rpc state eviscp)))

; Otherwise, we know that the car is followed by more elements.  So its rpc is
; 0.

        (t (cons-ppr1 (ppr1 (car lst) print-base print-radix width 0 state
                            eviscp)
                      (ppr1-lst (cdr lst) print-base print-radix width rpc
                                state eviscp)
                      width (ppr-flat-right-margin) eviscp))))

)

(defun newline (channel state)
  (declare (xargs :guard (and (state-p state)
                              (symbolp channel)
                              (open-output-channel-p channel :character state))))
  (princ$ #\Newline channel state))

(defun fmt-hard-right-margin (state)
  (the-fixnum
   (f-get-global 'fmt-hard-right-margin state)))

(defun fmt-soft-right-margin (state)
  (the-fixnum
   (f-get-global 'fmt-soft-right-margin state)))

(defun set-fmt-hard-right-margin (n state)
  (cond
   ((and (integerp n)
         (< 0 n))
    (f-put-global 'fmt-hard-right-margin
                  (the-half-fixnum! n 'set-fmt-hard-right-margin)
                  state))
   (t (let ((err (er hard 'set-fmt-hard-right-margin
                     "The fmt-hard-right-margin must be a positive ~
                      integer, but ~x0 is not."
                     n)))
        (declare (ignore err))
        state))))

(defun set-fmt-soft-right-margin (n state)
  (cond
   ((and (integerp n)
         (< 0 n))
    (f-put-global 'fmt-soft-right-margin
                  (the-half-fixnum! n 'set-fmt-soft-right-margin)
                  state))
   (t (let ((err (er hard 'set-fmt-soft-right-margin
                     "The fmt-soft-right-margin must be a positive ~
                      integer, but ~x0 is not."
                     n)))
        (declare (ignore err))
        state))))

(defun write-for-read (state)
  (declare (xargs :guard (and (state-p state)
                              (f-boundp-global 'write-for-read state))))
  (f-get-global 'write-for-read state))

(defun spaces1 (n col hard-right-margin channel state)
  (declare (type (signed-byte 30) n col hard-right-margin))
  (cond ((<= n 0) state)
        ((> col hard-right-margin)
         (pprogn (if (write-for-read state)
                     state
                   (princ$ #\\ channel state))
                 (newline channel state)
                 (spaces1 n 0 hard-right-margin channel state)))
        (t (pprogn (princ$ #\Space channel state)
                   (spaces1 (1-f n) (1+f col) hard-right-margin channel
                            state)))))

; The use of *acl2-built-in-spaces-array* to circumvent the call to spaces1
; under spaces has saved about 25% in GCL and a little more than 50% in
; Allegro.

(defun make-spaces-array-rec (n acc)
  (if (zp n)
      (cons (cons 0 "") acc)
    (make-spaces-array-rec
     (1- n)
     (cons
      (cons n
            (coerce (make-list n :initial-element #\Space) 'string))
      acc))))

(defun make-spaces-array (n)
  (compress1
   'acl2-built-in-spaces-array
   (cons `(:HEADER :DIMENSIONS (,(1+ n))
                   :MAXIMUM-LENGTH ,(+ 2 n)
                   :DEFAULT nil ; should be ignored
                   :NAME acl2-built-in-spaces-array)
         (make-spaces-array-rec n nil))))

(defconst *acl2-built-in-spaces-array*

; Keep the 200 below in sync with the code in spaces.

  (make-spaces-array 200))

(defun spaces (n col channel state)
  (declare (type (signed-byte 30) n col))
  (let ((hard-right-margin (fmt-hard-right-margin state))
        (result-col (+f n col)))
    (declare (type (signed-byte 30) hard-right-margin result-col))
    (if (and (<= result-col hard-right-margin)

; Keep the 200 below in sync with the code in *acl2-built-in-spaces-array*.

             (<= n 200))
        ;; actually (1+ hard-right-margin) would do
        (princ$ (aref1 'acl2-built-in-spaces-array
                       *acl2-built-in-spaces-array*
                       n)
                channel state)
      (spaces1 (the-fixnum! n 'spaces)
               (the-fixnum col)
               hard-right-margin
               channel state))))

(mutual-recursion

(defun flpr1 (x channel state eviscp)
  (cond ((atom x)
         (prin1$ x channel state))
        ((evisceratedp eviscp x)
         (princ$ (cdr x) channel state))
        ((and (eq (car x) 'quote)
              (consp (cdr x))
              (null (cddr x)))
         (pprogn (princ$ #\' channel state)
                 (flpr1 (cadr x) channel state eviscp)))
        (t (pprogn (princ$ #\( channel state)
                   (flpr11 x channel state eviscp)))))

(defun flpr11 (x channel state eviscp)
  (pprogn
   (flpr1 (car x) channel state eviscp)
   (cond ((null (cdr x)) (princ$ #\) channel state))
         ((or (atom (cdr x))
              (evisceratedp eviscp (cdr x)))
          (pprogn
           (princ$ " . " channel state)
           (flpr1 (cdr x) channel state eviscp)
           (princ$ #\) channel state)))
         (t (pprogn
             (princ$ #\Space channel state)
             (flpr11 (cdr x) channel state eviscp))))))

)

#+(and acl2-infix (not acl2-loop-only))
(defun-one-output print-flat-infix (x termp file eviscp)

; Print x flat (without terpri's) in infix notation to the open output
; stream file.  Give special treatment to :evisceration-mark iff
; eviscp.  We only call this function if flatsize-infix assures us
; that x will fit on the line.  See the Essay on Evisceration in this
; file to details on that subject.

  (declare (ignore termp eviscp))
  (let ((*print-case* :downcase)
        (*print-pretty* nil))
    (princ "$ " file)
    (prin1 x file)))

(defun flpr (x termp channel state eviscp)
  #-(and acl2-infix (not acl2-loop-only))
  (declare (ignore termp))
  #+(and acl2-infix (not acl2-loop-only))
  (cond ((and (live-state-p state)
              (output-in-infixp state))
         (print-flat-infix x termp
                           (get-output-stream-from-channel channel)
                           eviscp)
         (return-from flpr *the-live-state*)))
  (flpr1 x channel state eviscp))

(defun ppr2-flat (x channel state eviscp)

; We print the elements of x, separated by spaces.  If x is a non-nil atom, we
; print a dot and then x.

  (cond ((null x) state)
        ((or (atom x)
             (evisceratedp eviscp x))
         (pprogn (princ$ #\. channel state)
                 (princ$ #\Space channel state)
                 (flpr1 x channel state eviscp)))
        (t (pprogn
            (flpr1 (car x) channel state eviscp)
            (cond ((cdr x)
                   (pprogn (princ$ #\Space channel state)
                           (ppr2-flat (cdr x) channel state eviscp)))
                  (t state))))))

(mutual-recursion

(defun ppr2-column (lst loc col channel state eviscp)

; We print the elements of lst in a column.  The column number is col and we
; assume the print head is currently in column loc, loc <= col.  Thus, to
; indent to col we print col-loc spaces.  After every element of lst but the
; last, we print a newline.

  (cond ((null lst) state)
        (t (pprogn
            (spaces (+ col (- loc)) loc channel state)
            (ppr2 (car lst) col channel state eviscp)
            (cond ((null (cdr lst)) state)
                  (t (pprogn
                      (newline channel state)
                      (ppr2-column (cdr lst) 0 col
                                   channel state eviscp))))))))

(defun ppr2 (x col channel state eviscp)

; We interpret the ppr tuple x.

  (case
    (car x)
    (flat (ppr2-flat (cddr x) channel state eviscp))
    (matched-keyword
     (ppr2-flat (cddr x) channel state eviscp)) ; just like flat!
    (dot (princ$ #\. channel state))
    (quote (pprogn (princ$ #\' channel state)
                   (ppr2 (cddr x) (+ 1 col) channel state eviscp)))
    (keypair (pprogn
              (ppr2-flat (cddr (car (cddr x))) channel state eviscp)
              (princ$ #\Space channel state)
              (ppr2 (cdr (cddr x))
                    (+ col (+ 1 (cadr (car (cddr x)))))
                    channel state eviscp)))
    (wide (pprogn
           (princ$ #\( channel state)
           (ppr2-flat (cddr (car (cddr x))) channel state eviscp)
           (ppr2-column (cdr (cddr x))
                        (+ col (+ 1 (cadr (car (cddr x)))))
                        (+ col (+ 2 (cadr (car (cddr x)))))
                        channel state eviscp)
           (princ$ #\) channel state)))
    (otherwise (pprogn
                (princ$ #\( channel state)
                (ppr2 (car (cddr x)) (+ col (car x)) channel
                      state eviscp)
                (cond ((cdr (cddr x))
                       (pprogn
                        (newline channel state)
                        (ppr2-column (cdr (cddr x))
                                     0
                                     (+ col (car x))
                                     channel state eviscp)
                        (princ$ #\) channel state)))
                      (t (princ$ #\) channel state)))))))
)

; We used to set *fmt-ppr-indentation* below to 5, but it the indentation was
; sometimes odd because when printing a list, some elements could be indented
; and others not.  At any rate, it should be less than the
; fmt-hard-right-margin in order to preserve the invariant that fmt0 is called
; on columns that do not exceed this value.

(defconst *fmt-ppr-indentation* 0)

(defun ppr (x col channel state eviscp)

; If eviscp is nil, then we pretty print x as given.  Otherwise, x has been
; eviscerated and we give special importance to the *evisceration-mark*.  NOTE
; WELL: This function does not eviscerate -- it assumes the evisceration has
; been done if needed.

  (declare (type (signed-byte 30) col))
  (let ((fmt-hard-right-margin (fmt-hard-right-margin state)))
    (declare (type (signed-byte 30) fmt-hard-right-margin))
    (cond
     ((< col fmt-hard-right-margin)
      (ppr2 (ppr1 x (print-base) (print-radix)
                  (+f fmt-hard-right-margin (-f col))
                  0 state eviscp)
            col channel state eviscp))
     (t (let ((er
               (er hard 'ppr
                   "The `col' argument to ppr must be less than value ~
                    of the state global variable ~
                    fmt-hard-right-margin, but ~x0 is not less than ~
                    ~x1."
                   col fmt-hard-right-margin)))
          (declare (ignore er))
          state)))))

(defconst *illegal-fmt-keys*

; Warning: Keep this in sync with the cases in illegal-fmt-string.

  '(bad-evisc-tuple
    bad-tilde-&v-arg
    bad-tilde-*-arg
    bad-tilde-@-arg
    bad-tilde-c-arg
    bad-tilde-n-arg
    bad-tilde-s-arg
    bad-tilde-t-arg-natp
    bad-tilde-t-arg-not-natp
    bad-tilde-_-arg
    find-alternative-skip
    find-alternative-start
    find-alternative-start1-a
    find-alternative-start1-b
    find-alternative-stop
    tilde-arg-points-past-string
    unbound-tilde-arg
    unrecognized-tilde-arg))

(defun illegal-fmt-string (key)

; Warning: Keep the cases below in sync with *illegal-fmt-keys*.

  (declare (xargs :guard (member-eq key *illegal-fmt-keys*)))
  (case key
    (bad-evisc-tuple
     "In the fmt string displayed below, the tilde directive at location ~x0 ~
      associates character ~x1 with ~x2, which does not satisfy ~x3.~|~%~x4")
    (bad-tilde-&v-arg
     "The tilde directive at location ~x0 in the fmt string below uses the ~
      variable ~x1.  That ~s2 directive requires a true list, but it was ~
      supplied the value ~x3.~|~%~x4")
    (bad-tilde-*-arg
     "The tilde directive, ~~*, at location ~x0 in the fmt string below uses ~
      the variable ~x1.  That directive requires a list of the form (\"str0\" ~
      \"str1\" \"str2\" \"str3\" lst . alist) such that lst is a true-list ~
      and alist satisfies ~x2, but it was supplied the value ~x3.~|~%~x4")
    (bad-tilde-@-arg
     "The tilde-@ directive at position ~x0 of the string below is illegal ~
      because its variable evaluated to ~x1, which does not satisfy ~
      ~x2.~|~%~x3")
    (bad-tilde-c-arg
     "The tilde-c directive at position ~x0 of the string below is illegal ~
      because its variable evaluated to ~x1, which is not of the form (n . ~
      width), where n and width are integers and width is nonnegative.~|~%~x2")
    (bad-tilde-n-arg
     "The tilde directive at location ~x0 in the fmt string below uses the ~
      variable ~x1.  That ~s2 directive requires either an integer or a CONS ~
      whose CAR is an integer, but it was supplied the value ~x3.~|~%~x4")
    (bad-tilde-s-arg
     "The tilde-~s0 directive at position ~x1 of the string below is illegal ~
      because its variable evaluated to ~x2, which is not a symbol, a string, ~
      or a number.~|~%~x3")
    (bad-tilde-t-arg-natp
     "It is illegal to tab past the value of (@ fmt-hard-right-margin), ~x0, ~
      and hence the directive ~~t~s1 to tab to column ~x2 is illegal.  See ~
      :DOC set-fmt-hard-right-margin.")
    (bad-tilde-t-arg-not-natp
     "The tilde directive at location ~x0 in the fmt string below uses the ~
      variable ~x1.  That ~~t directive requires a natural number, but it was ~
      supplied the value ~x2.~|~%~x3")
    (bad-tilde-_-arg
     "The tilde-_ directive at position ~x0 of the string below is illegal ~
      because its variable evaluated to ~x1, which fails to be a natural ~
      number not exceeding ~x2.~|~%~x3")
    (find-alternative-skip
     "While looking for the terminating bracket of a tilde alternative ~
      directive in the string below we ran off the end of the string.~|~%~x0")
    (find-alternative-start
     "The tilde-# directive at ~x0 in the fmt string below must be followed ~
      immediately by ~~[.~|~%~x1")
    (find-alternative-start1-a
     "The tilde-# directive ~s0 at position ~x1 of the string below ~
      does not have enough alternative clauses.  When the terminal bracket ~
      was reached we still needed ~#2~[~/1 more alternative~/~x3 more ~
      alternatives~].~|~%~x4")
    (find-alternative-start1-b
     "While searching for the appropriate alternative clause of a tilde-# ~
      directive in the string below, we ran off the end of the string.~|~%~x0")
    (find-alternative-stop
     "While looking for the end of a tilde-# directive's alternative clause ~
      in the string below, we ran off the end of the string.~|~%~x0")
    (tilde-arg-points-past-string
     "The tilde directive at location ~x0 in the fmt string below requires ~
      that we look at the character ~x1 further down in the string.  But the ~
      string terminates at location ~x2.~|~%~x3")
    (unbound-tilde-arg
     "Unbound Fmt Variable.  The tilde directive at location ~x0 in the fmt ~
      string below uses the variable ~x1.  But this variable is not bound in ~
      the association list, ~x2, supplied with the fmt string.")
    (unrecognized-tilde-arg
     "The tilde directive at position ~x0 of the string below is ~
      unrecognized.~|~%~x1")
    (otherwise
     (er hard 'illegal-fmt-string
         "Implementation error in illegal-fmt-string: unknown key, ~x0."
         key))))

(defmacro illegal-fmt-msg (key &rest args)
  (declare (xargs :guard (member-eq key *illegal-fmt-keys*)))

; The final newline separates the string from a "See :DOC set-iprint" message,
; which can be printed by fmt-abbrev1 if a value is elided during printing an
; error message.

  `(msg "Illegal Fmt Syntax.  ~@0"
        (msg ,(illegal-fmt-string key)

; If you want to be able to trace illegal-fmt-string, then change the preceding
; s-expression to (illegal-fmt-string ',key) and the redefine functions that
; call this macro.

             ,@args)))

(defun scan-past-whitespace (s i maximum)
  (declare (type (unsigned-byte 29) i maximum)
           (type string s)
           (xargs :guard (and (<= i maximum)
                              (<= maximum (length s)))
                  :measure (nfix (- maximum i))
                  :ruler-extenders :all))
  (the-fixnum
   (cond ((not (mbt (and (integerp i) (integerp maximum))))
          maximum)
         ((< i maximum)
          (cond ((member (charf s i) '(#\Space #\Tab #\Newline))
                 (scan-past-whitespace s (+f i 1) maximum))
                (t i)))
         (t maximum))))

(defun zero-one-or-more (x)
  (declare (xargs :guard (or (integerp x)
                             (true-listp x))))
  (let ((n (cond ((integerp x) x)
                 (t (length x)))))
    (case n
          (0 0)
          (1 1)
          (otherwise 2))))

(defun find-alternative-skip (s i maximum quiet)

; This function finds the first position after a list of alternatives.  i is
; the value of find-alternative-stop, i.e., it points to the ~ in the ~/ or ~]
; that closed the alternative used.

; Suppose s is "~#7~[ab~/cd~/ef~]acl2".
;               01234567890123456789
; If i is 11, the answer is 17.

; In case of failure, this function logically returns (1+ maximum), but if
; quiet is nil then it causes a hard error.

  (declare (type (unsigned-byte 29) i maximum)
           (type string s)
           (xargs :guard (and (<= maximum (length s))
                              (< (length s) (fixnum-bound))
                              (<= i maximum))
                  :measure (nfix (- maximum i))
                  :ruler-extenders :lambdas))
  (the-fixnum
   (cond ((and (mbt (and (integerp i) (integerp maximum)))
               (< (1+f i) maximum))
          (let ((char-s-i (charf s i)))
            (declare (type character char-s-i))
            (case char-s-i
              (#\~
               (let ((i+2 (+f 2 i))
                     (char-s-1+i (charf s (1+f i))))
                 (declare (type character char-s-1+i)
                          (type (unsigned-byte 29) i+2))
                 (case char-s-1+i
                   (#\] i+2)
                   (#\[ (let ((new-i
                               (find-alternative-skip s i+2 maximum quiet)))
                          (declare (type (unsigned-byte 29) new-i))
                          (cond
                           ((and (mbt (and (integerp new-i)
                                           (< i new-i)))
                                 (not (eql new-i (1+f maximum))))
                            (find-alternative-skip s new-i maximum quiet))
                           (t
                            (1+f maximum)))))
                   (otherwise (find-alternative-skip s i+2 maximum quiet)))))
              (otherwise (find-alternative-skip s (+f 1 i) maximum quiet)))))
         (t (er-hard?-val?
             (1+f maximum) quiet 'find-alternative-skip
             "~@0"
             (illegal-fmt-msg find-alternative-skip s))))))

(defun find-alternative-start1 (x s i maximum quiet)

; This function recurs on x in support of find-alternative-start.  See the
; comment in find-alternative-start, in particular for a discussion of return
; values in the error cases.

; Suppose s is "~#7~[ab~/cd~/ef~]acl2".  The indices into s are:
;               01234567890123456789
; This function is supposed to be called with i pointing to the character
; immediately following "~[", which is 5 in this example.

  (declare (type (unsigned-byte 29) x i maximum)
           (type string s)
           (xargs :guard (and (<= maximum (length s))
                              (< (length s) (fixnum-bound))
                              (<= i maximum))
                  :measure (nfix (- maximum i))
                  :ruler-extenders :lambdas))
  (the-fixnum
   (cond ((= x 0) i)
         ((and (mbt (and (natp x)
                         (integerp i)
                         (integerp maximum)))
               (< (1+f i) maximum))
          (let ((char-s-i (charf s i)))
            (declare (type character char-s-i))
            (case char-s-i
              (#\~
               (let ((char-s-1+-i (charf s (1+f i))))
                 (declare (type character char-s-1+-i))
                 (case char-s-1+-i
                   (#\/ (find-alternative-start1
                         (1-f x) s (+f 2 i) maximum quiet))
                   (#\] (er-hard?-val?
                         (-f i) quiet 'find-alternative-start1
                         "~@0"
                         (illegal-fmt-msg find-alternative-start1-a
                                          "terminating"
                                          i
                                          (zero-one-or-more x)
                                          x
                                          s)))
                   (#\[ (let ((k (find-alternative-skip s (+f 2 i) maximum
                                                        quiet)))
                          (declare (type (unsigned-byte 29) k))
                          (cond
                           ((eql k (1+f maximum)) ; error case
                            maximum)
                           (t (find-alternative-start1 x s k maximum quiet)))))
                   (otherwise
                    (find-alternative-start1 x s (+f 2 i) maximum quiet)))))
              (otherwise
               (find-alternative-start1 x s (+f 1 i) maximum quiet)))))
         (t (er-hard?-val?
             (-f maximum) quiet 'find-alternative-start1
             "~@0"
             (illegal-fmt-msg find-alternative-start1-b s))))))

(defun fmt-char (s i j maximum err-flg)
  (declare (type (unsigned-byte 29) i maximum)

; We only increment i by a small amount, j.

           (type (integer 0 100) j)
           (type string s)
           (xargs :guard (and (<= maximum (length s)) ; typically, =
                              (<= (+ i j) maximum)
                              (or (null err-flg)
                                  (not (= (+ i j) maximum))))))
  (the character
       (cond ((< (+f i j) maximum)

; In spite of the guard, we do the inexpensive runtime check above since we may
; call fmt-char under a :program mode function, e.g., fmt.

              (charf s (+f i j)))
             (t
              (prog2$ ; return an arbitrary character
               (cond
                (err-flg

; This calculation is a bit ugly.  We are making it in April, 2018, after many
; years of an error message for ~X01 (or ~P34, etc. -- any of ~X, ~Y, ~P, or
; ~Q) stating that the tilde directive starts at location n where n-1 should be
; reported -- in which case, we need to look j+1 = 3 further down the string
; from the tilde.

                 (mv-let (i j)
                   (if (or (= 0 i)
                           (eql (charf s i) #\~)
                           (not (eql (charf s (1-f i)) #\~))) ; never true?
                       (mv i j)
                     (mv (1-f i) (1+f j)))
                   (er hard 'fmt-char
                       "~@0"
                       (illegal-fmt-msg
                        tilde-arg-points-past-string
                        i j maximum s))))
                (t nil))
               #\a)))))

(defun find-alternative-start (x s i maximum quiet)

; This function returns the index of the first character in the xth
; alternative, assuming i points to the ~ that begins the alternative
; directive.  If x is not an integer, we assume it is a non-empty list.  If its
; length is 1, pick the 0th alternative.  Otherwise, pick the 1st.  This means
; we can test on a list to get a "plural" test.

; Suppose s is "~#7~[ab~/cd~/ef~]acl2".  The indices into s are:
;               01234567890123456789
; This function is supposed to be called with i equal to the position of #\~ in
; "~#", which in this case is 0.  Suppose character #\7 is associated with 1.
; That's the value of x.  This function will return 9, the index of the
; beginning of alternative x.

; In the normal case, the index returned is strictly less than maximum-1.
; There are three error cases, where below, i is a positive integer.

; (- i)       A "~]" was reached before there were enough alternatives, and i
;             is the index of that "~".
;             [illegal-fmt-string: find-alternative-start1-a]

; -maximum    The indicated alternative was never reached.
;             [illegal-fmt-string: find-alternative-start1-b]

; maximum     A "~]" was not reached.
;             [illegal-fmt-string: find-alternative-skip]

; maximum+1   The "~[" was missing after the initial "~#c".
;             [illegal-fmt-string: find-alternative-start]

  (declare (type (unsigned-byte 29) i maximum)
           (type string s)
           (xargs :guard (and (<= maximum (length s))
                              (< (length s) (fixnum-bound))
                              (< (+ i 4) maximum))))
  (the-fixnum
   (let ((x (cond ((natp x) (the-fixnum! x 'find-alternative-start))
                  ((and (consp x)
                        (atom (cdr x)))
                   0)
                  (t 1))))
     (declare (type (unsigned-byte 29) x))
     (cond ((not (and (eql (the character (fmt-char s i 3 maximum t)) #\~)
                      (eql (the character (fmt-char s i 4 maximum t)) #\[)))
            (er-hard?-val?
             (1+f maximum) quiet 'find-alternative-start
             "~@0"
             (illegal-fmt-msg find-alternative-start i s)))
           (t (find-alternative-start1 x s (+f i 5) maximum quiet))))))

(defun find-alternative-stop (s i maximum quiet)

; This function finds the end of the alternative into which i is
; pointing.  i is usually the first character of the current alternative.
; The answer points to the ~ in the ~/ or ~] closing the alternative.

; Suppose s is "~#7~[ab~/cd~/ef~]acl2".
;               01234567890123456789
; and i is 9.  Then the answer is 11.

  (declare (type (unsigned-byte 29) i maximum)
           (type string s)
           (xargs :guard (and (<= maximum (length s))
                              (< (length s) (fixnum-bound))
                              (<= i maximum))
                  :measure (nfix (- (1+ maximum) i))
                  :ruler-extenders :lambdas))
  (the-fixnum
   (cond ((and (mbt (and (integerp i)
                         (integerp maximum)))
               (< (1+f i) maximum))
          (let ((char-s-i (charf s i)))
            (declare (type character char-s-i))
            (case char-s-i
              (#\~ (let ((char-s-1+i (charf s (1+f i))))
                     (declare (type character char-s-1+i))
                     (case char-s-1+i
                       (#\/ i)
                       (#\[ (let ((k (find-alternative-skip s (+f 2 i)
                                                            maximum quiet)))
                              (declare (type (unsigned-byte 29) k))
                              (cond
                               ((eql k (1+f maximum)) ; error case
                                k)
                               (t (find-alternative-stop s k maximum quiet)))))
                       (#\] i)
                       (otherwise (find-alternative-stop
                                   s (+f 2 i) maximum quiet)))))
              (otherwise (find-alternative-stop s (+f 1 i) maximum quiet)))))
         (t (er-hard?-val?
             (1+f maximum) quiet 'find-alternative-stop
             "~@0"
             (illegal-fmt-msg find-alternative-stop s))))))

(defun punctp (c)
  (if (member c '(#\. #\, #\: #\; #\? #\! #\) #\]))
      c
    nil))

(defun fmt-tilde-s1 (s i maximum col channel state)
  (declare (type (signed-byte 30) i maximum col)
           (type string s))
  (the2s
   (signed-byte 30)
   (cond ((not (< i maximum))
          (mv col state))
         ((and (> col (fmt-hard-right-margin state))
               (not (write-for-read state)))
          (pprogn
           (princ$ #\\ channel state)
           (newline channel state)
           (fmt-tilde-s1 s i maximum 0 channel state)))
         (t
          (let ((c (charf s i))
                (fmt-soft-right-margin (fmt-soft-right-margin state)))
            (declare (type character c)
                     (type (signed-byte 30) fmt-soft-right-margin))
            (cond ((and (> col fmt-soft-right-margin)
                        (not (write-for-read state))
                        (eql c #\Space))
                   (pprogn
                    (newline channel state)
                    (fmt-tilde-s1 s
                                  (scan-past-whitespace s (+f i 1) maximum)
                                  maximum 0 channel state)))
                  ((and (> col fmt-soft-right-margin)
                        (not (write-for-read state))
                        (or (eql c #\-)
                            (eql c #\_))
                        (not (int= (1+f i) maximum)))

; If we are beyond the soft right margin and we are about to print a
; hyphen or underscore and it is not the last character in the string,
; then print it and do a terpri.  If it is the last character, as it
; is in say, the function name "1-", then we don't do the terpri and
; hope there is a better place to break soon.  The motivating example
; for this was in seeing a list of function names get printed in a way
; that produced a comma as the first character of the newline, e.g.,
; "... EQL, 1+, 1-
; , ZEROP and PLUSP."

                   (pprogn
                    (princ$ c channel state)
                    (if (eql c #\-) state (princ$ #\- channel state))
                    (newline channel state)
                    (fmt-tilde-s1 s
                                  (scan-past-whitespace s (+f i 1) maximum)
                                  maximum 0 channel state)))
                  (t
                   (pprogn
                    (princ$ c channel state)
                    (fmt-tilde-s1 s (1+f i) maximum
                                  (if (eql c #\Newline)
                                      0
                                    (1+f col))
                                  channel state)))))))))

(defun fmt-tilde-cap-s1 (s i maximum col channel state)
  (declare (type (signed-byte 30) i maximum col)
           (type string s))
  (the2s
   (signed-byte 30)
   (cond ((not (< i maximum))
          (mv col state))
         (t
          (let ((c (charf s i)))
            (declare (type character c))
            (pprogn
             (princ$ c channel state)
             (fmt-tilde-cap-s1 s (1+f i) maximum
                               (if (eql c #\Newline)
                                   0
                                 (1+f col))
                               channel state)))))))

(defun fmt-var (s alist i maximum)

; We return the value associated in alist with the character at position i+2 of
; s.  We assume that there is a tilde character at position i or (less
; frequently) i-1.

; There is a call of assoc below that appears both in the guard and in the
; body.  This is not normally inefficient, since normally the guard will not be
; evaluated when under a call of a function whose symbol-class is :program or
; :common-lisp-compliant.  We want this assoc call in the guard in order to
; have confidence that we won't encounter the hard error below (rather than the
; alternative, which is to omit the assoc call from the guard and use (er hard?
; ...) instead of (er hard ...)).

  (declare (type (unsigned-byte 29) i maximum)
           (type string s)
           (xargs :guard (and (<= maximum (length s)) ; typically, =
                              (< (+ i 2) maximum)
                              (character-alistp alist)
                              (assoc (the character
                                          (fmt-char s i 2 maximum t))
                                     alist))))
  (let ((x (assoc (the character (fmt-char s i 2 maximum t)) alist)))
    (cond (x (cdr x))
          (t (let ((tilde-position

; This calculation is a bit ugly.  We are making it in April, 2018, after many
; years of an error message for ~X01 (or ~P34, etc. -- any of ~X, ~Y, ~P, or
; ~Q) stating that the tilde directive starts at location n where n-1 should be
; reported.

                    (if (eql (charf s i) #\~)
                        i
                      (1-f i))))
               (er hard 'fmt-var
                   "~@0"
                   (illegal-fmt-msg
                    unbound-tilde-arg
                    tilde-position (char s (+f i 2)) alist s)))))))

(defun splat-atom (x print-base print-radix indent col channel state)

; See also splat-atom!, which ignores margins.

  (let* ((sz (flsz-atom x print-base print-radix 0 state))
         (too-bigp (> (+ col sz) (fmt-hard-right-margin state))))
    (pprogn (if too-bigp
                (pprogn (newline channel state)
                        (spaces indent 0 channel state))
                state)
            (prin1$ x channel state)
            (mv (if too-bigp (+ indent sz) (+ col sz))
                state))))

(defun splat-atom! (x print-base print-radix col channel state)

; See also splat-atom, which takes account of margins by possibly printing
; newlines.

  (pprogn (prin1$ x channel state)
          (mv (flsz-atom x print-base print-radix col state)
              state)))

(defun splat-string (x indent col channel state)

; This variant of splat-atom prints the string x flat, without the quotes.

  (let* ((sz (the-half-fixnum! (length x) 'splat-string))
         (too-bigp (> (+ col sz) (fmt-hard-right-margin state))))
    (pprogn (if too-bigp
                (pprogn (newline channel state)
                        (spaces indent 0 channel state))
                state)
            (princ$ x channel state)
            (mv (if too-bigp (+ indent sz) (+ col sz))
                state))))

; Splat, below, prints out an arbitrary ACL2 object flat, introducing
; the single-gritch notation for quote and breaking lines between lexemes
; to avoid going over the hard right margin.  It indents all but the first
; line by indent spaces.

(mutual-recursion

(defun splat (x print-base print-radix indent eviscp col channel state)
  (cond ((atom x)
         (splat-atom x print-base print-radix indent col channel state))
        ((evisceratedp eviscp x)
         (splat-string (cdr x) indent col channel state))
        ((and (eq (car x) 'quote)
              (consp (cdr x))
              (null (cddr x)))
         (pprogn (princ$ #\' channel state)
                 (splat (cadr x) print-base print-radix indent eviscp
                        (1+ col) channel state)))
        (t (pprogn (princ$ #\( channel state)
                   (splat1 x print-base print-radix indent eviscp (1+ col)
                           channel state)))))

(defun splat1 (x print-base print-radix indent eviscp col channel state)
  (mv-let (col state)
          (splat (car x) print-base print-radix indent eviscp col channel state)
          (cond ((null (cdr x))
                 (pprogn (princ$ #\) channel state)
                         (mv (1+ col) state)))
                ((atom (cdr x))
                 (cond ((> (+ 3 col) (fmt-hard-right-margin state))
                        (pprogn (newline channel state)
                                (spaces indent 0 channel state)
                                (princ$ ". " channel state)
                                (mv-let (col state)
                                        (splat (cdr x)
                                               print-base print-radix indent
                                               eviscp
                                               (+ indent 2)
                                               channel state)
                                        (pprogn (princ$ #\) channel state)
                                                (mv (1+ col) state)))))
                       (t (pprogn
                           (princ$ " . " channel state)
                           (mv-let (col state)
                                   (splat (cdr x)
                                          print-base print-radix indent eviscp
                                          (+ 3 col)
                                          channel state)
                                   (pprogn (princ$ #\) channel state)
                                           (mv (1+ col) state)))))))
                (t (pprogn
                    (princ$ #\Space channel state)
                    (splat1 (cdr x) print-base print-radix indent eviscp
                            (1+ col) channel state))))))

)

(defun number-of-digits (n print-base print-radix)

; We compute the width of the field necessary to express the integer n
; in the given print-base.  We assume minus signs are printed but plus
; signs are not.  Thus, if n is -123 we return 4, if n is 123 we
; return 3.

  (cond ((< n 0) (1+ (number-of-digits (abs n) print-base print-radix)))
        ((< n print-base)
         (cond ((null print-radix)
                1)
               ((int= print-base 10) ; `.' suffix
                2)
               (t ; #b, #o, or #x prefix
                3)))
        (t (1+ (number-of-digits (floor n print-base) print-base
                                 print-radix)))))

(defun left-pad-with-blanks (n width col channel state)

; Print the integer n right-justified in a field of width width.
; We return the final column (assuming we started in col) and state.

  (declare (type (signed-byte 30) col))
  (the2s
   (signed-byte 30)
   (let ((d (the-half-fixnum! (number-of-digits n (print-base) (print-radix))
                              'left-pad-with-blanks)))
     (declare (type (signed-byte 30) d))
     (cond ((>= d width)
            (pprogn (prin1$ n channel state)
                    (mv (+ col d) state)))
           (t (pprogn
               (spaces (- width d) col channel state)
               (prin1$ n channel state)
               (mv (the-fixnum! (+ col width) 'left-pad-with-blanks)
                   state)))))))

(defmacro maybe-newline (body)

; This macro is used in fmt0 to force a newline only when absolutely
; necessary.  It knows the locals of fmt0, in particular, col,
; channel, and state.  We wrap this macro around code that is about to
; print a character at col.  Once upon a time we just started fmt0
; with a newline if we were past the hard right margin, but that
; produced occasional lines that ended naturally at the hard right
; margin and then had a backslash inserted in anticipation of the 0
; characters to follow.  It was impossible to tell if more characters
; follow because there may be tilde commands between where you are and
; the end of the line, and they may or may not print things.

  `(mv-letc (col state)
            (cond
             ((and (> col (fmt-hard-right-margin state))
                   (not (write-for-read state)))
              (pprogn (princ$ #\\ channel state)
                      (newline channel state)
                      (mv 0 state)))
             (t (mv col state)))
            ,body))

; To support the convention that er, fmt, and even individual fmt
; commands such as ~X can control their own evisceration parameters,
; we now introduce the idea of an evisceration tuple, or evisc-tuple.

(defun evisc-tuple (print-level print-length alist hiding-cars)

; See :doc set-evisc-tuple for a lot of information about evisc-tuples.  Also
; see the Essay on Iprinting for a related topic.

; This is really just a record constructor, but we haven't got defrec
; yet so we do it by hand.  See set-evisc-tuple.

; We sometimes write out constant evisc tuples!  However they are commented
; nearby with (evisc-tuple ...).

; The primitive consumers of evisc tuples all call eviscerate-top or
; eviscerate-stobjs-top.

;         car   cadr        caddr        cadddr

  (list alist   print-level print-length hiding-cars))

(defun standard-evisc-tuplep (x)
  (declare (xargs :guard t))
  (or (null x)
      (and (true-listp x)
           (= (length x) 4)
           (alistp (car x))
           (or (null (cadr x))
               (integerp (cadr x)))
           (or (null (caddr x))
               (integerp (caddr x)))
           (symbol-listp (cadddr x)))))

(defun world-evisceration-alist (state alist)
  (declare (xargs :stobjs state))
  (let ((wrld (w state)))
    (cond ((null wrld) ; loading during the build
           alist)
          (t (cons (cons wrld *evisceration-world-mark*)
                   alist)))))

(defun abbrev-evisc-tuple (state)

; As of January 2009 the abbrev-evisc-tuple is used in error, warning$,
; observation, pstack, break-on-error, and miscellany such as running commands
; where little output is desired, say for :ubt or rebuild.  We don't put this
; complete of a specification into the documentation, however, in case later we
; tweak the set of uses of the abbrev-evisc-tuple.  This comment should
; similarly not be viewed as definitive if it is long after January 2009.

  (declare (xargs :stobjs state
                  :guard (f-boundp-global 'abbrev-evisc-tuple state)))
  (let ((evisc-tuple (f-get-global 'abbrev-evisc-tuple state)))
    (cond
     ((eq evisc-tuple :default)
      (cons (world-evisceration-alist state nil)
            '(5 7 nil)))
     (t evisc-tuple))))

(defmacro gag-mode ()
  '(f-get-global 'gag-mode state))

(defun term-evisc-tuple (flg state)

; This evisceration tuple is used when we are printing terms or lists of terms.
; If state global 'term-evisc-tuple has value other than :default, then we
; return that value.  Otherwise:

; We don't hide the world or state because they aren't (usually) found in
; terms.  This saves us a little time.  If the global value of
; 'eviscerate-hide-terms is t, we print (HIDE ...) as <hidden>.  Otherwise not.
; Flg controls whether we actually eviscerate on the basis of structural depth
; and length.  If flg is t we do.  The choice of the print-length 4 is
; motivated by the idea of being able to print IF as (IF # # #) rather than (IF
; # # ...).  Print-level 3 lets us print a clause as ((NOT (PRIMEP #)) ...)
; rather than ((NOT #) ...).

  (let ((evisc-tuple (f-get-global 'term-evisc-tuple state)))
    (cond ((not (eq evisc-tuple :default))
           evisc-tuple)
          ((f-get-global 'eviscerate-hide-terms state)
           (cond (flg
;;; (evisc-tuple 3 4 nil '(hide))
                  '(nil 3 4 (hide)))
                 (t
;;; (evisc-tuple nil nil nil '(hide))
                  '(nil nil nil (hide)))))
          (flg ;;; (evisc-tuple 3 4 nil nil)
           '(nil 3 4 nil))
          (t nil))))

(defun gag-mode-evisc-tuple (state)
  (cond ((gag-mode)
         (let ((val (f-get-global 'gag-mode-evisc-tuple state)))
           (if (eq val :DEFAULT)
               nil
             val)))
        (t (term-evisc-tuple nil state))))

(defun ld-evisc-tuple (state)
  (let ((evisc-tuple (f-get-global 'ld-evisc-tuple state)))
    (assert$ (not (eq evisc-tuple :default)) ; only abbrev, term evisc-tuples
             evisc-tuple)))

#+(and acl2-infix (not acl2-loop-only))
(defun-one-output print-infix (x termp width rpc col file eviscp)

; X is an s-expression denoting a term (if termp = t) or an evg (if
; termp = nil).  File is an open output file.  Prettyprint x in infix
; notation to file.  If eviscp is t then we are to give special treatment to
; the :evisceration-mark; otherwise not.

; This hook is modeled after the ACL2 pretty-printer, which has the following
; additional features.  These features need not be implemented in the infix
; prettyprinter.  The printer is assumed to be in column col, where col=0 means
; it is on the left margin.  We are supposed to print our first character in
; that column.  We are supposed to print in a field of width width.  That is,
; the largest column into which we might print is col+width-2.  Finally, assume
; that on the last line of the output somebody is going to write rpc additional
; characters and arrange for this not to overflow the col+width-2 limit.  Rpc
; is used when, for example, we plan to print some punctuation, like a comma,
; after a form and want to ensure that we can do it without overflowing the
; right margin.  (One might think that the desired effect could be obtained by
; setting width smaller, but that is wrong because it narrows the whole field
; and we only want to guarantee space on the last line.)  Here is an example.
; Use ctrl-x = in emacs to see what columns things are in.  The semi-colons are
; in column 0.  Pretend they are all spaces, as they would be if the printing
; had been done by fmt-ppr.

; (foobar
;   (here is a long arg)
;   a)

; Here, col = 2, width = 23, and rpc = 19!

; Infix Hack:
; We simply print out $ followed by the expression.  We print the
; expression in lower-case.

  (declare (ignore termp width rpc col eviscp))
  (let ((*print-case* :downcase)
        (*print-pretty* t))
    (princ "$ " file)
    (prin1 x file)))

(defun fmt-ppr (x termp width rpc col channel state eviscp)
  (declare (type (signed-byte 30) col))
  #-(and acl2-infix (not acl2-loop-only))
  (declare (ignore termp))
  #+(and acl2-infix (not acl2-loop-only))
  (cond
   ((and (live-state-p state)
         (output-in-infixp state))
    (print-infix x termp width rpc col
                 (get-output-stream-from-channel channel)
                 eviscp)
    (return-from fmt-ppr *the-live-state*)))
  (ppr2 (ppr1 x (print-base) (print-radix) width rpc state eviscp)
        col channel state eviscp))

(defun scan-past-empty-fmt-directives (s alist i maximum)

; We return a natural number j with i <= j < maximum, such that fmt printing of
; the characters of s from i through j-1, with respect to alist, produces no
; output.  It is thus always sound to return i, but we aim to do better than
; that when feasible.

  (declare (type (unsigned-byte 29) i maximum)
           (type string s))
  (the-fixnum
   (cond
    ((>= i maximum) i)
    (t (let ((c (charf s i)))
         (declare (type character c))
         (cond
          ((eql c #\~)
           (let ((fmc (the character (fmt-char s i 1 maximum t))))
             (declare (type character fmc))
             (case
               fmc
               ((#\s #\S)
                (cond
                 ((equal (fmt-var s alist i maximum) "")
                  (scan-past-empty-fmt-directives s alist (+f i 3) maximum))
                 (t i)))
               (#\@
                (let ((val (fmt-var s alist i maximum)))
                  (cond
                   ((equal val "")
                    (scan-past-empty-fmt-directives s alist (+f i 3) maximum))
                   ((atom val) i)
                   ((equal (car val) "")
                    (scan-past-empty-fmt-directives s alist (+f i 3) maximum))
                   ((not (stringp (car val))) ; always false?
                    i)
                   (t (let ((len (length (car val)))
                            (alist1 (append (cdr val) alist)))
                        (if (equal (scan-past-empty-fmt-directives
                                    (car val) alist1 0 len)
                                   len)
                            (scan-past-empty-fmt-directives s alist (+f i 3)
                                                            maximum)
                          i))))))
               (#\#
                (let* ((n (find-alternative-start
                           (fmt-var s alist i maximum) s i maximum nil))
                       (m (find-alternative-stop s n maximum nil))
                       (o (find-alternative-skip s m maximum nil)))
                  (declare (type (signed-byte 30) n)
                           (type (unsigned-byte 29) m o))
                  (cond
                   ((or (= n m) ; optimization
                        (= (scan-past-empty-fmt-directives s alist n m) m))
                    (scan-past-empty-fmt-directives s alist o maximum))
                   (t i))))
               (otherwise i))))
          (t i)))))))

(mutual-recursion

(defun fmt0* (str0 str1 str2 str3 lst alist col channel state evisc-tuple)

; This odd function prints out the members of lst.  If the list has no
; elements, str0 is used.  If the list has 1 element, str1 is used
; with #\* bound to the element.  If the list has two elements, str2
; is used with #\* bound to the first element and then str1 is used
; with #\* bound to the second.  If the list has more than two
; elements, str3 is used with #\* bound successively to each element
; until there are only two left.  The function is used in the
; implementation of ~&, ~v, and ~*.

  (declare (type (signed-byte 30) col)
           (type string str0 str1 str2 str3))
  (the2s
   (signed-byte 30)
   (cond ((null lst)
          (fmt0 str0 alist 0 (the-fixnum! (length str0) 'fmt0*) col nil channel
                state evisc-tuple))
         ((null (cdr lst))
          (fmt0 str1
                (cons (cons #\* (car lst)) alist)
                0 (the-fixnum! (length str1) 'fmt0*) col nil channel
                state evisc-tuple))
         ((null (cddr lst))
          (mv-letc (col state)
                   (fmt0 str2
                         (cons (cons #\* (car lst)) alist)
                         0 (the-fixnum! (length str2) 'fmt0*)
                         col nil channel state evisc-tuple)
                   (fmt0* str0 str1 str2 str3 (cdr lst) alist col channel
                          state evisc-tuple)))
         (t (mv-letc (col state)
                     (fmt0 str3
                           (cons (cons #\* (car lst)) alist)
                           0 (the-fixnum! (length str3) 'fmt0*)
                           col nil channel state evisc-tuple)
                     (fmt0* str0 str1 str2 str3 (cdr lst) alist col channel
                            state evisc-tuple))))))

(defun fmt0&v (flg lst punct col channel state evisc-tuple)
  (declare (type (signed-byte 30) col))
  (the2s
   (signed-byte 30)
   (case flg
     (&
      (case
          punct
        (#\. (fmt0* "" "~x*." "~x* and " "~x*, " lst nil col channel
                    state evisc-tuple))
        (#\, (fmt0* "" "~x*," "~x* and " "~x*, " lst nil col channel
                    state evisc-tuple))
        (#\: (fmt0* "" "~x*:" "~x* and " "~x*, " lst nil col channel
                    state evisc-tuple))
        (#\; (fmt0* "" "~x*;" "~x* and " "~x*, " lst nil col channel
                    state evisc-tuple))
        (#\! (fmt0* "" "~x*!" "~x* and " "~x*, " lst nil col channel
                    state evisc-tuple))
        (#\) (fmt0* "" "~x*)" "~x* and " "~x*, " lst nil col channel
                    state evisc-tuple))
        (#\? (fmt0* "" "~x*?" "~x* and " "~x*, " lst nil col channel
                    state evisc-tuple))
        (otherwise
         (fmt0* "" "~x*" "~x* and " "~x*, " lst nil col channel
                state evisc-tuple))))
     (otherwise
      (case
          punct
        (#\. (fmt0* "" "~x*." "~x* or " "~x*, " lst nil col channel
                    state evisc-tuple))
        (#\, (fmt0* "" "~x*," "~x* or " "~x*, " lst nil col channel
                    state evisc-tuple))
        (#\: (fmt0* "" "~x*:" "~x* or " "~x*, " lst nil col channel
                    state evisc-tuple))
        (#\; (fmt0* "" "~x*;" "~x* or " "~x*, " lst nil col channel
                    state evisc-tuple))
        (#\! (fmt0* "" "~x*!" "~x* or " "~x*, " lst nil col channel
                    state evisc-tuple))
        (#\) (fmt0* "" "~x*)" "~x* or " "~x*, " lst nil col channel
                    state evisc-tuple))
        (#\? (fmt0* "" "~x*?" "~x* or " "~x*, " lst nil col channel
                    state evisc-tuple))
        (otherwise
         (fmt0* "" "~x*" "~x* or " "~x*, " lst nil col channel
                state evisc-tuple)))))))

(defun spell-number (n cap col channel state evisc-tuple)

; If n is an integerp we spell out the name of the cardinal number n
; (for a few cases) or else we just print the decimal representation
; of n.  E.g., n=4 makes us spell "four".  If n is a consp then we
; assume its car is an integer and we spell the corresponding ordinal
; number, e.g., n= '(4 . th) makes us spell "fourth".  We capitalize
; the word if cap is t.

  (declare (type (signed-byte 30) col))
  (the2s
   (signed-byte 30)
   (let ((str
          (cond ((integerp n)
                 (cond ((int= n 0) (if cap "Zero" "zero"))
                       ((int= n 1) (if cap "One" "one"))
                       ((int= n 2) (if cap "Two" "two"))
                       ((int= n 3) (if cap "Three" "three"))
                       ((int= n 4) (if cap "Four" "four"))
                       ((int= n 5) (if cap "Five" "five"))
                       ((int= n 6) (if cap "Six" "six"))
                       ((int= n 7) (if cap "Seven" "seven"))
                       ((int= n 8) (if cap "Eight" "eight"))
                       ((int= n 9) (if cap "Nine" "nine"))
                       ((int= n 10) (if cap "Ten" "ten"))
                       ((int= n 11) (if cap "Eleven" "eleven"))
                       ((int= n 12) (if cap "Twelve" "twelve"))
                       ((int= n 13) (if cap "Thirteen" "thirteen"))
                       (t "~x0")))
                ((and (consp n)
                      (<= 0 (car n))
                      (<= (car n) 13))
                 (cond ((int= (car n) 0) (if cap "Zeroth" "zeroth"))
                       ((int= (car n) 1) (if cap "First" "first"))
                       ((int= (car n) 2) (if cap "Second" "second"))
                       ((int= (car n) 3) (if cap "Third" "third"))
                       ((int= (car n) 4) (if cap "Fourth" "fourth"))
                       ((int= (car n) 5) (if cap "Fifth" "fifth"))
                       ((int= (car n) 6) (if cap "Sixth" "sixth"))
                       ((int= (car n) 7) (if cap "Seventh" "seventh"))
                       ((int= (car n) 8) (if cap "Eighth" "eighth"))
                       ((int= (car n) 9) (if cap "Ninth" "ninth"))
                       ((int= (car n) 10) (if cap "Tenth" "tenth"))
                       ((int= (car n) 11) (if cap "Eleventh" "eleventh"))
                       ((int= (car n) 12) (if cap "Twelfth" "twelfth"))
                       (t (if cap "Thirteenth" "thirteenth"))))
                (t (let ((d (mod (abs (car n)) 10)))

; We print -11th, -12th, -13th, ... -20th, -21st, -22nd, etc., though
; what business anyone has using negative ordinals I can't imagine.

                     (cond ((or (int= d 0)
                                (> d 3)
                                (int= (car n) -11)
                                (int= (car n) -12)
                                (int= (car n) -13))
                            "~x0th")
                           ((int= d 1) "~x0st")
                           ((int= d 2) "~x0nd")
                           (t "~x0rd")))))))

     (fmt0 (the-string! str 'spell-number)
           (cond ((integerp n)
                  (cond ((and (<= 0 n) (<= n 13)) nil)
                        (t (list (cons #\0 n)))))
                 (t (cond ((and (<= 0 (car n)) (<= (car n) 13)) nil)
                          (t (list (cons #\0 (car n)))))))
           0 (the-fixnum! (length str) 'spell-number)
           col nil channel state evisc-tuple))))

(defun fmt-tilde-s (s col channel state)

; If s is a symbol or a string, we print it out, breaking on hyphens but not
; being fooled by fmt directives inside it.  We also allow s to be a number
; (not sure why this was ever allowed, but we continue to support it).  We
; return the new col and state.

  (declare (type (signed-byte 30) col))
  (the2s
   (signed-byte 30)
   (cond
    ((acl2-numberp s)
     (pprogn (prin1$ s channel state)
             (mv (flsz-atom s (print-base) (print-radix) col state) state)))
    ((stringp s)
     (fmt-tilde-s1 s 0 (the-fixnum! (length s) 'fmt-tilde-s) col
                   channel state))
    (t
     (let ((str (symbol-name s)))
       (cond
        ((keywordp s)
         (cond
          ((needs-slashes str state)
           (splat-atom s (print-base) (print-radix) 0 col channel state))
          (t (fmt0 ":~s0" (list (cons #\0 str)) 0 4 col nil channel state nil))))
        ((symbol-in-current-package-p s state)
         (cond
          ((needs-slashes str state)
           (splat-atom s (print-base) (print-radix) 0 col channel state))
          (t (fmt-tilde-s1 str 0
                           (the-fixnum! (length str) 'fmt-tilde-s)
                           col channel state))))
        (t
         (let ((p (symbol-package-name s)))
           (cond
            ((or (needs-slashes p state)
                 (needs-slashes str state))
             (splat-atom s (print-base) (print-radix) 0 col channel state))
            (t (fmt0 "~s0::~-~s1"
                     (list (cons #\0 p)
                           (cons #\1 str))
                     0 10 col nil channel state nil)))))))))))

(defun fmt-tilde-cap-s (s col channel state)

; This variant of fmt-tilde-s avoids printing newlines during the printing of
; s.

  (declare (type (signed-byte 30) col))
  (the2s
   (signed-byte 30)
   (cond
    ((acl2-numberp s)
     (splat-atom! s (print-base) (print-radix) col channel state))
    ((stringp s)
     (fmt-tilde-cap-s1 s 0 (the-fixnum! (length s) 'fmt-tilde-s) col
                       channel state))
    (t
     (let ((str (symbol-name s)))
       (cond
        ((keywordp s)
         (cond
          ((needs-slashes str state)
           (splat-atom! s (print-base) (print-radix) col channel state))
          (t (fmt0 ":~S0" (list (cons #\0 str)) 0 4 col nil channel state nil))))
        ((symbol-in-current-package-p s state)
         (cond
          ((needs-slashes str state)
           (splat-atom! s (print-base) (print-radix) col channel state))
          (t (fmt-tilde-cap-s1 str 0
                               (the-fixnum! (length str) 'fmt-tilde-s)
                               col channel state))))
        (t
         (let ((p (symbol-package-name s)))
           (cond
            ((or (needs-slashes p state)
                 (needs-slashes str state))
             (splat-atom! s (print-base) (print-radix) col channel state))
            (t (fmt0 "~S0::~S1"
                     (list (cons #\0 p)
                           (cons #\1 str))
                     0 10 col nil channel state nil)))))))))))

(defun fmt0 (s alist i maximum col pn channel state evisc-tuple)

; Warning: Keep this in sync with fmx-cw-msg-1-body and :DOC fmt.

; Pn is either nil or else punctuation to print when we reach the end of s,
; presumably not in column 0.

  (declare (xargs :guard ; incomplete guard

; The guard on this function is quite incomplete.  Some runtime checks can
; result in hard errors even when the guard is met.  We have attempted to
; eliminate raw Lisp errors,

                  (and (stringp s)
                       (character-alistp alist)
                       (standard-evisc-tuplep evisc-tuple)))
           (type (unsigned-byte 29) i maximum col)
           (type string s))
  (the2s
   (unsigned-byte 29)
   (cond
    ((>= i maximum)
     (cond (pn (pprogn (princ$ pn channel state)
                       (mv (the (unsigned-byte 29) (1+f col)) state)))
           (t (mv (the (unsigned-byte 29) col) state))))
    (t
     (let ((c (charf s i)))
       (declare (type character c))
       (cond
        ((eql c #\~)
         (let ((fmc (the character (fmt-char s i 1 maximum t))))
           (declare (type character fmc))
           (case
             fmc
             ((#\p #\q #\P #\Q #\x #\y #\X #\Y)

; The only difference between pqPQ and xyXY is that the former can cause infix
; printing.  (But see the comment below about "hyphenate" for how we can cause
; the latter to enable hyphenation.)  However, as of this writing (Jan. 2009)
; it is far from clear that infix printing still works; so we consider it to be
; deprecated.  Infix printing assumes the term has already been untranslated.

; The difference between the lowercase directives and the uppercase ones is
; that the uppercase ones take two fmt-vars, e.g., ~X01, and use the contents
; of the second one as the evisceration value.  Otherwise the uppercase
; directives behave as their lowercase counterparts.

; On symbols, ~x and ~y are alike and just print starting in col.  On non-
; symbols they both prettyprint.  But ~y starts printing in col while ~x may do
; a terpri and indent first.  ~x concludes with a terpri if it put out a terpri
; before printing.  ~y always concludes with a terpri, so you know where you
; end up.

              (maybe-newline
               (let* ((caps (or (eql fmc #\P) (eql fmc #\Q)
                                (eql fmc #\X) (eql fmc #\Y)))
                      (px (or (eql fmc #\p) (eql fmc #\P)
                              (eql fmc #\x) (eql fmc #\X)))
                      (qy (not px))
                      (pq (or (eql fmc #\p) (eql fmc #\P)
                              (eql fmc #\q) (eql fmc #\Q)))
                      (local-evisc-tuple
                       (cond (caps
                              (let ((x (fmt-var s alist (1+f i) maximum)))
                                (cond
                                 ((not (standard-evisc-tuplep x))
                                  (er hard 'fmt0
                                      "~@0"
                                      (illegal-fmt-msg
                                       bad-evisc-tuple
                                       i
                                       (charf s (+f i 3))
                                       x 'standard-evisc-tuplep s)))
                                 (t x))))
                             (t evisc-tuple)))
                      (evisc-table (table-alist 'evisc-table (w state)))
                      (eviscp (or local-evisc-tuple evisc-table)))
                 (mv-let
                   (x state)
                   (cond (eviscp (eviscerate-top
                                  (fmt-var s alist i maximum)
                                  (cadr local-evisc-tuple)  ;;; print-level
                                  (caddr local-evisc-tuple) ;;; print-length
                                  (car local-evisc-tuple)   ;;; alist
                                  evisc-table
                                  (cadddr local-evisc-tuple) ;;; hiding-cars
                                  state))
                         (t (mv (fmt-var s alist i maximum)
                                state)))

; Through Version_3.4, ACL2 could hyphenate rule names during proof commentary
; because of the following COND branch in the case of ~x/~y/~X/~Y (though
; fmt-symbol-name has since been renamed as fmt-tilde-s).  We have decided to
; opt instead for uniform treatment of ~x/~y/~X/~Y and ~p/~q/~P/~Q, modulo
; potential support for infix printing for the latter group (which we may
; eliminate in the future).  By avoiding hyphenation we make it easier for a
; user to grab a rule name from the output, though now one might want to do
; some hyphenation by hand when preparing proof output for publication.

;                   ((and (or (symbolp x)
;                             (acl2-numberp x))
;                         (member-eq fmc '(#\x #\y #\X #\Y)))
;                    (mv-letc (col state)
;                             (fmt-tilde-s x col channel state)
;                             (fmt0 s alist
;                                   (+f i (if (or (eql fmc #\X)
;                                                 (eql fmc #\Y))
;                                             4
;                                           3))
;                                   maximum col nil channel state
;                                   evisc-tuple)))

                   (let* ((fmt-hard-right-margin (fmt-hard-right-margin state))
                          (sz (flsz x pq col fmt-hard-right-margin state
                                    eviscp))
                          (incr (the-fixnum (if caps 4 3)))
                          (c (fmt-char s i incr maximum nil))
                          (punctp (punctp c))
                          (print-pn (and pn
                                         (not punctp) ; optimization
                                         (= (+f i incr) maximum)))
                          (p+ (if (or punctp print-pn) 1 0)))
                     (declare (type (unsigned-byte 29)
                                    fmt-hard-right-margin sz incr))
                     (cond
                      ((and px
                            (> col (the-fixnum *fmt-ppr-indentation*))
                            (> (+f p+ sz) fmt-hard-right-margin)
                            (not (> (+f p+
                                        (flsz x
                                              pq
                                              (the-fixnum
                                               *fmt-ppr-indentation*)
                                              fmt-hard-right-margin
                                              state eviscp))
                                    fmt-hard-right-margin)))
                       (pprogn
                        (newline channel state)
                        (spaces1 (the-fixnum *fmt-ppr-indentation*) 0
                                 fmt-hard-right-margin
                                 channel state)
                        (fmt0 s alist i maximum
                              (the-fixnum *fmt-ppr-indentation*)
                              pn channel state evisc-tuple)))
                      ((or qy
                           (> (the-fixnum (+f p+ sz))
                              fmt-hard-right-margin))
                       (pprogn
                        (cond (qy state)
                              ((= col 0) state)
                              (t (newline channel state)))
                        (if qy
                            state
                          (spaces1 (the-fixnum *fmt-ppr-indentation*)
                                   0 fmt-hard-right-margin channel state))
                        (let* ((i1 (the-fixnum (if punctp
                                                   (+f i incr 1)
                                                 (+f i incr))))
                               (i2 (if qy ; then respect trailing whitespace
                                       i1
                                     (scan-past-whitespace s i1 maximum))))
                          (declare (type (unsigned-byte 29) i1 i2))
                          (pprogn
                           (fmt-ppr
                            x
                            pq
                            (+f fmt-hard-right-margin
                                (-f (if qy
                                        col
                                      *fmt-ppr-indentation*)))
                            p+
                            (the-fixnum
                             (if qy
                                 col
                               *fmt-ppr-indentation*))
                            channel state eviscp)
                           (cond (punctp (princ$ c channel state))
                                 (print-pn (princ$ pn channel state))
                                 (t state))
                           (newline channel state)
                           (fmt0 s alist i2 maximum 0
                                 (and (not print-pn) pn)
                                 channel state
                                 evisc-tuple)))))
                      (t (pprogn
                          (flpr x pq channel state eviscp)
                          (fmt0 s alist
                                (+f i (if caps
                                          4
                                        3))
                                maximum sz pn
                                channel state evisc-tuple)))))))))
             (#\@ (let ((s1 (fmt-var s alist i maximum))
                        (i0 (scan-past-empty-fmt-directives s alist (+f i 3)
                                                            maximum)))
                    (declare (type (unsigned-byte 29) i0))
                    (mv-let (i1 pn pn@)
                      (cond ((< i0 maximum)
                             (let ((punctp (punctp (charf s i0))))
                               (cond (punctp (mv (1+f i0) pn punctp))
                                     (t (mv i0 pn nil)))))
                            (t ; print any pending punctuation with s1
                             (mv i0 nil pn)))
                      (mv-letc (col state)
                               (cond ((stringp s1)
                                      (fmt0 s1 alist 0
                                            (the-fixnum! (length s1) 'fmt0)
                                            col pn@ channel state evisc-tuple))
                                     ((msgp s1)
                                      (fmt0 (car s1)
                                            (append (cdr s1) alist)
                                            0
                                            (the-fixnum! (length (car s1)) 'fmt0)
                                            col pn@ channel state evisc-tuple))
                                     (t (mv (er-hard-val
                                             0 'fmt0 "~@0"
                                             (illegal-fmt-msg
                                              bad-tilde-@-arg
                                              i s1 'msgp s))
                                            state)))
                               (fmt0 s alist i1 maximum col pn
                                     channel state evisc-tuple)))))
             (#\# (let* ((n (find-alternative-start
                             (fmt-var s alist i maximum) s i maximum nil))
                         (m (find-alternative-stop s n maximum nil))
                         (o (find-alternative-skip s m maximum nil)))
                    (declare (type (signed-byte 30) n)
                             (type (unsigned-byte 29) m o))
                    (mv-let (pn1 pn2 o)
                      (cond ((= o maximum)
                             (mv pn nil o))
                            ((punctp (charf s o))
                             (mv (charf s o) pn (1+f o)))
                            (t
                             (mv nil pn o)))
                      (declare (type (unsigned-byte 29) o))
                      (mv-letc (col state)
                               (fmt0 s alist
                                     (the-fixnum n)
                                     (the-fixnum m)
                                     col pn1 channel state evisc-tuple)
                               (fmt0 s alist (the-fixnum o) maximum col pn2
                                     channel state evisc-tuple)))))
             (#\* (let ((x (fmt-var s alist i maximum)))
                    (cond
                     ((or (< (len x) 5)
                          (not (stringp (car x)))
                          (not (stringp (cadr x)))
                          (not (stringp (caddr x)))
                          (not (stringp (cadddr x)))
                          (not (true-listp (car (cddddr x))))
                          (not (character-alistp (cdr (cddddr x)))))
                      (mv (er-hard-val
                           0 'fmt0 "~@0"
                           (illegal-fmt-msg
                            bad-tilde-*-arg
                            i
                            (char s (+f i 2))
                            'character-alistp
                            x
                            s))
                          state))
                     (t
                      (mv-letc (col state)
                               (fmt0* (car x) (cadr x) (caddr x) (cadddr x)
                                      (car (cddddr x))
                                      (append (cdr (cddddr x)) alist)
                                      col channel state evisc-tuple)
                               (fmt0 s alist (+f i 3) maximum col pn
                                     channel state evisc-tuple))))))
             ((#\& #\v)
              (let ((i+3 (+f i 3))
                    (lst (fmt-var s alist i maximum)))
                (declare (type (unsigned-byte 29) i+3))
                (cond
                 ((not (true-listp lst))
                  (mv (er-hard-val
                       0 'fmt0 "~@0"
                       (illegal-fmt-msg
                        bad-tilde-&v-arg
                        i
                        (char s (+f i 2))
                        (if (eql fmc #\&) "~&" "~v")
                        lst
                        s))
                      state))
                 (t
                  (mv-letc (col state)
                           (fmt0&v (if (eql fmc #\&) '& 'v)
                                   lst
                                   (punctp (and (< i+3 maximum)
                                                (char s i+3)))
                                   col channel state evisc-tuple)
                           (fmt0 s alist
                                 (the-fixnum
                                  (cond
                                   ((punctp (and (< i+3 maximum)
                                                 (char s i+3)))
                                    (+f i 4))
                                   (t i+3)))
                                 maximum
                                 col pn channel state evisc-tuple))))))
             ((#\n #\N)
              (let ((k (fmt-var s alist i maximum)))
                (cond
                 ((not (or (integerp k)
                           (and (consp k)
                                (integerp (car k)))))
                  (mv (er-hard-val
                       0 'fmt0 "~@0"
                       (illegal-fmt-msg
                        bad-tilde-n-arg
                        i
                        (char s (+f i 2))
                        (if (eql fmc #\n) "~n" "~N")
                        k
                        s))
                      state))
                 (t
                  (maybe-newline
                   (mv-letc (col state)
                            (spell-number k
                                          (eql fmc #\N)
                                          col channel state evisc-tuple)
                            (fmt0 s alist (+f i 3) maximum col pn channel
                                  state evisc-tuple)))))))
             (#\t (maybe-newline
                   (let ((goal-col (fmt-var s alist i maximum))
                         (fmt-hard-right-margin (fmt-hard-right-margin state)))
                     (declare (type (unsigned-byte 29) fmt-hard-right-margin))
                     (pprogn
                      (cond ((or (not (natp goal-col))
                                 (> goal-col fmt-hard-right-margin))
                             (let ((er
                                    (if (natp goal-col)
                                        (er hard 'fmt0
                                            "~@0"
                                            (illegal-fmt-msg
                                             bad-tilde-t-arg-natp
                                             fmt-hard-right-margin
                                             (string (fmt-char s i 2 maximum t))
                                             goal-col))
                                      (er hard 'fmt0
                                          "~@0"
                                          (illegal-fmt-msg
                                           bad-tilde-t-arg-not-natp
                                           i
                                           (char s (+f i 2))
                                           goal-col
                                           s)))))
                               (declare (ignore er))
                               state))
                            ((>= col (the-fixnum goal-col))
                             (pprogn (newline channel state)
                                     (spaces1 (the-fixnum goal-col) 0
                                              fmt-hard-right-margin
                                              channel state)))
                            (t (spaces1 (-f goal-col col) col
                                        fmt-hard-right-margin
                                        channel state)))
                      (fmt0 s alist (+f i 3) maximum
                            (the-fixnum goal-col)
                            pn channel state evisc-tuple)))))
             (#\c (maybe-newline
                   (let ((pair (fmt-var s alist i maximum)))
                     (cond ((and (consp pair)
                                 (integerp (car pair))
                                 (integerp (cdr pair))
                                 (>= (cdr pair) 0))
                            (mv-letc (col state)
                                     (left-pad-with-blanks (car pair)
                                                           (cdr pair)
                                                           col channel state)
                                     (fmt0 s alist (+f i 3) maximum col pn
                                           channel state evisc-tuple)))
                           (t (mv (er-hard-val
                                   0 'fmt0 "~@0"
                                   (illegal-fmt-msg
                                    bad-tilde-c-arg
                                    i pair s))
                                  state))))))
             ((#\f #\F)
              (let ((evisc-table
                     (append? (car evisc-tuple) ;;; alist

; We normally would pass the alist above into eviscerate-top below, as the
; argument just above evisc-table, and bind evisc-table to the table-alist call
; on the line just below.  However, the call of splat below expects a single
; alist.

                              (table-alist 'evisc-table (w state)))))
                (mv-let
                  (x state)
                  (cond (evisc-table (eviscerate-top
                                      (fmt-var s alist i maximum)
                                      nil ;;; print-level
                                      nil ;;; print-length
                                      nil
                                      evisc-table
                                      nil ;;; hiding-cars
                                      state))
                        (t (mv (fmt-var s alist i maximum)
                               state)))
                  (maybe-newline
                   (mv-letc (col state)
                            (splat x
                                   (print-base) (print-radix)
                                   (if (eql fmc #\F) (1+f col) 0)
                                   evisc-table col channel state)
                            (fmt0 s alist (+f i 3) maximum col pn channel
                                  state evisc-tuple))))))
             ((#\s #\S)
              (let ((x (fmt-var s alist i maximum)))
                (cond
                 ((or (symbolp x)
                      (stringp x)
                      (acl2-numberp x))
                  (maybe-newline
                   (mv-letc (col state)
                            (if (eql fmc #\s)
                                (fmt-tilde-s x col channel state)
                              (fmt-tilde-cap-s x col channel state))
                            (fmt0 s alist (+f i 3) maximum col pn channel
                                  state evisc-tuple))))
                 (t (mv (er-hard-val
                         0 'fmt0 "~@0"
                         (illegal-fmt-msg
                          bad-tilde-s-arg
                          (if (eql fmc #\s) "s" "S")
                          i x s))
                        state)))))
             (#\Space (let ((exceeds-margin
                             (or (> col (the-fixnum
                                         (fmt-hard-right-margin state)))
                                 (> col (the-fixnum
                                         (fmt-soft-right-margin state))))))
                        (pprogn
                         (cond (exceeds-margin (newline channel state))
                               (t state))
                         (princ$ #\Space channel state)
                         (fmt0 s alist (+f i 2) maximum
                               (cond (exceeds-margin
                                      1)
                                     (t (1+f col)))
                               pn channel state evisc-tuple))))
             (#\_ (maybe-newline
                   (let ((fmt-hard-right-margin
                          (fmt-hard-right-margin state)))
                     (declare (type (unsigned-byte 29) fmt-hard-right-margin))
                     (let* ((n0 (fmt-var s alist i maximum))
                            (n (if (and (natp n0)
                                        (<= n0 (floor (fixnum-bound) 2)))
                                   n0 ; (the-half-fixnum! n0 'fmt0)
                                 (er-hard-val
                                  0 'fmt0 "~@0"
                                  (illegal-fmt-msg
                                   bad-tilde-_-arg
                                   i n0 (floor (fixnum-bound) 2) s)))))
                       (declare (type (unsigned-byte 29) n))
                       (let ((new-col (+f col n)))
                         (declare (type (unsigned-byte 29) new-col))
                         (pprogn
                          (spaces n col channel state)
                          (cond
                           ((> new-col fmt-hard-right-margin)
                            (newline channel state))
                           (t state))
                          (fmt0 s alist (+f i 3) maximum
                                (the-fixnum
                                 (cond
                                  ((> new-col fmt-hard-right-margin)
                                   0)
                                  (t new-col)))
                                pn channel state evisc-tuple)))))))
             (#\Newline
              (fmt0 s alist (scan-past-whitespace s (+f i 2) maximum)
                    maximum col pn channel state evisc-tuple))
             (#\| (pprogn
                   (if (int= col 0) state (newline channel state))
                   (fmt0 s alist (+f i 2)
                         maximum 0 pn channel state evisc-tuple)))
             (#\% (pprogn
                   (newline channel state)
                   (fmt0 s alist (+f i 2)
                         maximum 0 pn channel state evisc-tuple)))
             (#\~ (maybe-newline
                   (pprogn
                    (princ$ #\~ channel state)
                    (fmt0 s alist (+f i 2) maximum (1+f col) pn channel
                          state evisc-tuple))))
             (#\- (cond ((> col (fmt-soft-right-margin state))
                         (pprogn
                          (princ$ #\- channel state)
                          (newline channel state)
                          (fmt0 s alist
                                (scan-past-whitespace s (+f i 2) maximum)
                                maximum 0 pn channel state evisc-tuple)))
                        (t (fmt0 s alist (+f i 2) maximum col pn channel
                                 state evisc-tuple))))
             (otherwise (mv (er-hard-val
                             0 'fmt0 "~@0"
                             (illegal-fmt-msg
                              unrecognized-tilde-arg
                              i s))
                            state)))))
        ((and (> col (fmt-soft-right-margin state))
              (eql c #\Space))
         (pprogn (newline channel state)
                 (fmt0 s alist
                       (scan-past-whitespace s (+f i 1) maximum)
                       maximum
                       0 pn channel state evisc-tuple)))
        ((and (>= col (fmt-soft-right-margin state))
              (eql c #\-))
         (pprogn (princ$ c channel state)
                 (newline channel state)
                 (fmt0 s alist
                       (scan-past-whitespace s (+f i 1) maximum)
                       maximum
                       0 pn channel state evisc-tuple)))
;       ((and (eql c #\Space)
; I cut out this code in response to Kaufmann's complaint 38.  The idea is
; *not* to ignore spaces after ~% directives.  I've left the code here to
; remind me of what I used to do, in case I see output that is malformed.
;            (int= col 0))
;       (fmt0 s alist (+f i 1) maximum 0 channel state evisc-tuple))
        (t (maybe-newline
            (pprogn (princ$ c channel state)
                    (fmt0 s alist (+f i 1) maximum
                          (if (eql c #\Newline) 0 (+f col 1))
                          pn channel state evisc-tuple))))))))))

)

(defun tilde-*-&v-strings (flg lst punct)

; This function returns an object that when bound to #\0 will cause
; ~*0 to print a conjunction (flg='&) or disjunction (flg='v) of the
; strings in lst, followed by punctuation punct, which must be #\. or
; #\,.

; WARNING:  This displayed strings are not equal to the strings in lst
; because whitespace may be inserted!

; ~& doesn't print a list of short strings very well because the first
; group is printed flat across the line, then when the line gets too
; long, the next string is indented and followed by a newline, which
; allows another bunch to be printed flat.  This function prints them
; with ~s which actually breaks the strings up internally in a way
; that does not preserve their equality.  "history-management.lisp"
; might have a newline inserted after the hyphen.

  (case
   flg
   (&
    (case
     punct
     (#\. (list "" "\"~s*\"." "\"~s*\" and " "\"~s*\", " lst))
     (#\, (list "" "\"~s*\"," "\"~s*\" and " "\"~s*\", " lst))
     (#\: (list "" "\"~s*\":" "\"~s*\" and " "\"~s*\", " lst))
     (#\; (list "" "\"~s*\";" "\"~s*\" and " "\"~s*\", " lst))
     (#\! (list "" "\"~s*\"!" "\"~s*\" and " "\"~s*\", " lst))
     (#\) (list "" "\"~s*\")" "\"~s*\" and " "\"~s*\", " lst))
     (#\? (list "" "\"~s*\"?" "\"~s*\" and " "\"~s*\", " lst))
     (otherwise
      (list "" "\"~s*\"" "\"~s*\" and " "\"~s*\", " lst))))
   (otherwise
    (case
     punct
     (#\. (list "" "\"~s*\"." "\"~s*\" or " "\"~s*\", " lst))
     (#\, (list "" "\"~s*\"," "\"~s*\" or " "\"~s*\", " lst))
     (#\: (list "" "\"~s*\":" "\"~s*\" or " "\"~s*\", " lst))
     (#\; (list "" "\"~s*\";" "\"~s*\" or " "\"~s*\", " lst))
     (#\! (list "" "\"~s*\"!" "\"~s*\" or " "\"~s*\", " lst))
     (#\) (list "" "\"~s*\")" "\"~s*\" or " "\"~s*\", " lst))
     (#\? (list "" "\"~s*\"?" "\"~s*\" or " "\"~s*\", " lst))
     (otherwise
      (list "" "\"~s*\"" "\"~s*\" or " "\"~s*\", " lst))))))

(defun fmt1 (str alist col channel state evisc-tuple)

; WARNING:  The master copy of the tilde-directives list is in :DOC fmt.

  (declare (xargs :guard ; incomplete guard
                  (and (stringp str)
                       (character-alistp alist)
                       (standard-evisc-tuplep evisc-tuple)))
           (type (signed-byte 30) col))
  (the2s
   (signed-byte 30)
   (mv-let (col state)
           (fmt0 (the-string! str 'fmt1) alist 0
                 (the-fixnum! (length str) 'fmt1)
                 (the-fixnum! col 'fmt1)
                 nil
                 channel state evisc-tuple)
           (declare (type (signed-byte 30) col))
           (prog2$ (and (eq channel *standard-co*)
                        (maybe-finish-output$ *standard-co* state))
                   (mv col state)))))

(defun fmt (str alist channel state evisc-tuple)

; WARNING: IF you change the list of tilde-directives, change the copy of it in
; the :DOC for fmt1 and fms.

; For a discussion of our style of pretty-printing, see
; http://www.cs.utexas.edu/~boyer/pretty-print.pdf.

  (declare (xargs :guard ; incomplete guard
                  (and (stringp str)
                       (character-alistp alist)
                       (standard-evisc-tuplep evisc-tuple))))
  (the2s
   (signed-byte 30)
   (pprogn
    (newline channel state)
    (fmt1 str alist 0 channel state evisc-tuple))))

(defun fms (str alist channel state evisc-tuple)

; WARNING: The master copy of the tilde-directives list is in :DOC fmt.

  (declare (xargs :guard ; incomplete guard
                  (and (stringp str)
                       (character-alistp alist)
                       (standard-evisc-tuplep evisc-tuple))))
  (pprogn
   (newline channel state)
   (mv-let (col state)
           (fmt1 str alist 0 channel state evisc-tuple)
           (declare (ignore col))
           state)))

(defun fmt1! (str alist col channel state evisc-tuple)

; WARNING: The master copy of the tilde-directives list is in :DOC fmt.

  (declare (xargs :guard ; incomplete guard
                  (and (stringp str)
                       (character-alistp alist)
                       (standard-evisc-tuplep evisc-tuple))))
  (mv-let (erp col state)
          (state-global-let*
           ((write-for-read t))
           (mv-let (col state)
                   (fmt1 str alist col channel state evisc-tuple)
                   (mv nil col state)))
          (declare (ignore erp))
          (mv col state)))

(defun fmt! (str alist channel state evisc-tuple)

; WARNING: The master copy of the tilde-directives list is in :DOC fmt.

  (declare (xargs :guard ; incomplete guard
                  (and (stringp str)
                       (character-alistp alist)
                       (standard-evisc-tuplep evisc-tuple))))
  (mv-let (erp col state)
          (state-global-let*
           ((write-for-read t))
           (mv-let (col state)
                   (fmt str alist channel state evisc-tuple)
                   (mv nil col state)))
          (declare (ignore erp))
          (mv col state)))

(defun fms! (str alist channel state evisc-tuple)

; WARNING: The master copy of the tilde-directives list is in :DOC fmt.

  (mv-let (erp val state)
          (state-global-let*
           ((write-for-read t))
           (pprogn (fms str alist channel state evisc-tuple)
                   (mv nil nil state)))
          (declare (ignore erp val))
          state))

(defmacro fmx (str &rest args)
  (declare (xargs :guard (<= (length args) 10)))
  `(fmt1 ,str
         ,(make-fmt-bindings '(#\0 #\1 #\2 #\3 #\4
                               #\5 #\6 #\7 #\8 #\9)
                             args)
         0 *standard-co* state nil))

(defmacro fmx-cw-msg-1-body ()

; Warning: Keep this in sync with fmt0 and :DOC fmt.

; This unusual way of specifying a function body is useful for sharing code
; between the definition of fmx-cw-msg-1 and the rewrite rule,
; fmx-cw-msg-1-opener.

; Warning: To see the effect of changing this definition during an interactive
; session, you will also need to redefine fmx-cw-msg-1 (say, by redefining it
; to be a term different from, but provably equal to, (fmx-cw-msg-1-body)).

  '(cond
    ((zp clk) ; impossible?
     (msg "Stack depth exceeded for guard check!"))
    ((or (not (mbt (natp i)))
         (not (mbt (natp maximum)))
         (>= i maximum))
     nil)
    (t
     (let ((c0 (the character (charf s i)))
           (i+1 (1+f i))
           (clk-1 (1-f clk)))
       (declare (type character c0)
                (type (unsigned-byte 29) i+1 clk-1))
       (cond
        ((eql c0 #\~)
         (cond
          ((not (< i+1 maximum))
           (illegal-fmt-msg
            tilde-arg-points-past-string
            i 1 maximum s))
          (t
           (let ((c1 (the character (charf s i+1))))
             (declare (type character c1))
             (case
               c1
               ((#\Space #\Newline #\| #\% #\~ #\-)
                nil)
               (otherwise
                (let ((i+2 (+f i 2)))
                  (declare (type (unsigned-byte 29) i+2))
                  (cond
                   ((not (< i+2 maximum))
                    (illegal-fmt-msg
                     tilde-arg-points-past-string
                     i 2 maximum s))
                   (t
                    (let* ((c2 (the character (charf s i+2)))
                           (pair2 (assoc c2 alist))
                           (val2 (cdr pair2))
                           (i+3 (+f i 3)))
                      (declare (type character c2)
                               (type (unsigned-byte 29) i+3))
                      (cond
                       ((not pair2)
                        (illegal-fmt-msg
                         unbound-tilde-arg
                         i c2 alist s))
                       (t
                        (case
                          c1
                          ((#\p #\q #\x #\y)
                           (fmx-cw-msg-1 s alist i+3 maximum clk-1))
                          ((#\P #\Q #\X #\Y)
                           (cond
                            ((not (< i+3 maximum))
                             (illegal-fmt-msg
                              tilde-arg-points-past-string
                              i 3 maximum s))
                            (t
                             (let* ((c3 (the character (charf s i+3)))
                                    (pair3 (assoc c3 alist))
                                    (val3 (cdr pair3)))
                               (declare (type character c3))
                               (cond
                                ((not pair3)
                                 (illegal-fmt-msg
                                  unbound-tilde-arg
                                  i c3 alist s))
                                ((not (standard-evisc-tuplep val3))
                                 (illegal-fmt-msg
                                  bad-evisc-tuple
                                  i c3 val3 'standard-evisc-tuplep s))
                                (t
                                 (fmx-cw-msg-1 s alist
                                               (+f i 4)
                                               maximum
                                               clk-1)))))))
                          (#\@
                           (or
                            (cond
                             ((and (stringp val2)
                                   (< (length val2) (fixnum-bound)))
                              (fmx-cw-msg-1
                               val2 alist 0
                               (length val2)
                               clk-1))
                             ((and (consp val2)
                                   (msgp val2)
                                   (< (length (car val2)) (fixnum-bound)))
                              (fmx-cw-msg-1 (car val2)
                                            (append (cdr val2) alist)
                                            0
                                            (length (car val2))
                                            clk-1))
                             (t
                              (illegal-fmt-msg
                               bad-tilde-@-arg
                               i val2 'character-alistp s)))
                            (fmx-cw-msg-1 s alist i+3 maximum clk-1)))
                          (#\#
                           (cond
                            ((not (< i+3 maximum))
                             (illegal-fmt-msg
                              tilde-arg-points-past-string
                              i 3 maximum s))
                            (t
                             (let ((i+4 (+f i 4)))
                               (declare (type (unsigned-byte 29) i+4))
                               (cond
                                ((not (< i+4 maximum))
                                 (illegal-fmt-msg
                                  tilde-arg-points-past-string
                                  i 4 maximum s))
                                (t
                                 (let ((n (find-alternative-start
                                           c2 s i maximum t))
                                       (max+1 (1+f maximum)))
                                   (declare (type (signed-byte 30) n max+1))
                                   (cond
                                    ((= n max+1)
                                     (illegal-fmt-msg
                                      find-alternative-start i s))
                                    ((= n maximum)
                                     (illegal-fmt-msg
                                      find-alternative-skip s))
                                    ((= n (-f maximum))
                                     (illegal-fmt-msg
                                      find-alternative-start1-b s))
                                    ((< n 0)
                                     (illegal-fmt-msg
                                      find-alternative-start1-a
                                      "starting"
                                      i
                                      (zero-one-or-more (-f n))
                                      (-f n)
                                      s))
                                    (t
                                     (let ((m (find-alternative-stop
                                               s n maximum t)))
                                       (declare (type (unsigned-byte 29)
                                                      m))
                                       (cond
                                        ((eql m max+1)
                                         (illegal-fmt-msg
                                          find-alternative-stop
                                          s))
                                        (t
                                         (let ((o (find-alternative-skip
                                                   s m maximum t)))
                                           (declare
                                            (type (unsigned-byte 29) o))
                                           (cond
                                            ((eql m max+1)
                                             (illegal-fmt-msg
                                              find-alternative-skip
                                              s))
                                            (t
                                             (or (fmx-cw-msg-1
                                                  s alist n m clk-1)
                                                 (fmx-cw-msg-1
                                                  s alist o maximum
                                                  clk-1)))))))))))))))))
                          ((#\& #\v)
                           (cond
                            ((not (true-listp val2))
                             (illegal-fmt-msg
                              bad-tilde-&v-arg
                              i c2
                              (if (eql c1 #\&) "~&" "~v")
                              val2 s))
                            (t
                             (fmx-cw-msg-1 s alist i+3 maximum clk-1))))
                          (#\*
                           (cond
                            ((not (and (>= (len val2) 5)
                                       (character-alistp
                                        (cdr (cddddr val2)))))
                             (illegal-fmt-msg
                              bad-tilde-*-arg
                              i c2 'character-alistp val2 s))
                            (t
                             (fmx-cw-msg-1 s alist i+3 maximum clk-1))))
                          ((#\n #\N)
                           (cond
                            ((not (or (integerp val2)
                                      (and (consp val2)
                                           (integerp (car val2)))))
                             (illegal-fmt-msg
                              bad-tilde-n-arg
                              i
                              c2
                              (if (eql c1 #\n) "~n" "~N")
                              val2
                              s))
                            (t
                             (fmx-cw-msg-1 s alist i+3 maximum clk-1))))
                          (#\t
                           (let ((goal-col val2))
                             (cond
                              ((not (natp goal-col))
                               (illegal-fmt-msg
                                bad-tilde-t-arg-not-natp
                                i
                                c2
                                goal-col
                                s))
                              (nil ; (> goal-col fmt-hard-right-margin)

; We don't have state available, so we cannot obtain the current value of the
; state global, fmt-hard-right-margin.  Thus we use a condition of nil above.
; We could use the default value for that global, as shown below, but that
; might frustrate users who set a bigger value and thus expect to be able to
; tab past the default.

                               (illegal-fmt-msg
                                bad-tilde-t-arg-natp
                                *fmt-hard-right-margin-default*
                                (string c2)
                                goal-col))
                              (t
                               (fmx-cw-msg-1 s alist i+3 maximum clk-1)))))
                          (#\c
                           (let ((pair val2))
                             (cond
                              ((and (consp pair)
                                    (integerp (car pair))
                                    (integerp (cdr pair))
                                    (>= (cdr pair) 0))
                               (fmx-cw-msg-1 s alist i+3 maximum clk-1))
                              (t
                               (illegal-fmt-msg
                                bad-tilde-c-arg
                                i pair s)))))
                          ((#\f #\F)
                           (fmx-cw-msg-1 s alist i+3 maximum clk-1))
                          ((#\s #\S)
                           (let ((x val2))
                             (cond
                              ((or (symbolp x)
                                   (stringp x)
                                   (acl2-numberp x))
                               (fmx-cw-msg-1 s alist i+3 maximum clk-1))
                              (t
                               (illegal-fmt-msg
                                bad-tilde-s-arg
                                (if (eql c1 #\s) "s" "S")
                                i x s)))))
                          (#\_
                           (cond
                            ((and (natp c2)
                                  (<= c2 ; for the-half-fixnum!
                                      (floor (fixnum-bound) 2)))
                             (fmx-cw-msg-1 s alist i+3 maximum clk-1))
                            (t
                             (illegal-fmt-msg
                              bad-tilde-_-arg
                              i c2 (floor (fixnum-bound) 2) s))))
                          ((#\Newline #\| #\% #\~ #\-)
                           (fmx-cw-msg-1 s alist i+2 maximum clk-1))
                          (otherwise
                           (illegal-fmt-msg
                              unrecognized-tilde-arg
                              i s)))))))))))))))
        (t (fmx-cw-msg-1 s alist i+1 maximum clk-1)))))))

(defun fmx-cw-msg-1 (s alist i maximum clk)
  (declare (type (unsigned-byte 29) i maximum clk)
           (type string s)
           (xargs :guard (and (character-alistp alist)
                              (< (length s) (fixnum-bound))
                              (<= maximum (length s)))
                  :guard-hints (("Goal" :in-theory (disable nth)))
                  :measure (nfix clk)))
  (fmx-cw-msg-1-body))

(defun fmx-cw-msg (str alist)
  (declare (xargs :guard t))
  (cond
   ((not (stringp str))
    (msg "Not a string:~|~x0" str))
   ((not (character-alistp alist))
    (msg "Not a character-alistp:~|~x0" alist))
   (t (let ((len (length str)))
        (cond
         ((not (< len (fixnum-bound)))
          (msg "String is too long:~|~x0" str))
         (t (fmx-cw-msg-1 str alist 0 (length str) (fixnum-bound))))))))

(defun fmx-cw-fn-guard (str alist)
  (declare (xargs :guard t))
  (null (fmx-cw-msg str alist)))

(defun fmx-cw-fn (str alist)
  (declare (xargs :guard (fmx-cw-fn-guard str alist)))
  (fmt-to-comment-window str alist 0 nil nil))

(defun fmx!-cw-fn (str alist)
  (declare (xargs :guard (fmx-cw-fn-guard str alist)))
  (fmt-to-comment-window! str alist 0 nil nil))

(defmacro fmx-cw (str &rest args)

; WARNING: Keep this in sync with cw, cw!, and other fmx-cw macros.

; This is a guarded version of cw.
; See the comments there, including this warning:

; WARNING: Keep this in sync with cw!.

  `(fmx-cw-fn ,str
              (pairlis2 '(#\0 #\1 #\2 #\3 #\4
                          #\5 #\6 #\7 #\8 #\9)
                        (list ,@args))))

(defmacro fmx!-cw (str &rest args)

; WARNING: Keep this in sync with cw, cw!, and other fmx-cw macros.

; This is a guarded version of cw.
; See the comments there, including this warning:

; WARNING: Keep this in sync with cw!.

  `(fmx!-cw-fn ,str
               (pairlis2 '(#\0 #\1 #\2 #\3 #\4
                           #\5 #\6 #\7 #\8 #\9)
                         (list ,@args))))

(defun fmt-doc-example1 (lst i)
  (cond ((null lst) nil)
        (t (cons (cons "~c0 (~n1)~tc~y2~|"
                       (list (cons #\0 (cons i 5))
                             (cons #\1 (list i))
                             (cons #\2 (car lst))))
                 (fmt-doc-example1 (cdr lst) (1+ i))))))

(defun fmt-doc-example (x state)
  (fmt "Here is a true list:  ~x0.  It has ~#1~[no elements~/a single ~
        element~/~n2 elements~], ~@3~%~%We could print each element in square ~
        brackets:~%(~*4).  And if we wished to itemize them into column 15 we ~
        could do it like this~%0123456789012345~%~*5End of example."
       (list (cons #\0 x)
             (cons #\1 (cond ((null x) 0) ((null (cdr x)) 1)(t 2)))
             (cons #\2 (length x))
             (cons #\3 (cond ((< (length x) 3) "and so we can't print the third one!")
                             (t (cons "the third of which is ~x0."
                                      (list (cons #\0 (caddr x)))))))
             (cons #\4 (list "[empty]"
                             "[the end: ~y*]"
                             "[almost there: ~y*], "
                             "[~y*], "
                             x))
             (cons #\5 (list* "" "~@*" "~@*" "~@*"
                              (fmt-doc-example1 x 0)
                              (list (cons #\c 15)))))
         *standard-co* state nil))

(defconst *see-doc-set-iprint*

; We give this string a name so that it can be referenced in books; see for
; example community book books/misc/wet.lisp.

  "~|(See :DOC set-iprint to be able to see elided values in this message.)")

(defun fmt-abbrev1 (str alist col channel state suffix-msg)
  (pprogn
   (f-put-global 'evisc-hitp-without-iprint nil state)
   (mv-let (col state)
           (fmt1 str alist col channel state (abbrev-evisc-tuple state))
           (fmt1 "~@0~@1"
                 (list
                  (cons #\0
                        (cond ((f-get-global 'evisc-hitp-without-iprint
                                             state)
                               (assert$
                                (not (iprint-enabledp state))
                                *see-doc-set-iprint*))
                              (t "")))
                  (cons #\1 suffix-msg))
                 col channel state nil))))

(defun fmt-abbrev (str alist col channel state suffix-msg)
  (mv-let (col state)
          (fmt-abbrev1 str alist col channel state suffix-msg)
          (declare (ignore col))
          state))

(defconst *fmt-ctx-spacers*
  '(defun
     #+:non-standard-analysis defun-std
     mutual-recursion
     defuns
     defthm
     #+:non-standard-analysis defthm-std
     defaxiom
     defconst
     defstobj defabsstobj
     defpkg
     deflabel
     deftheory
     defchoose
     verify-guards
     verify-termination
     defmacro
     in-theory
     in-arithmetic-theory
     regenerate-tau-database
     push-untouchable
     remove-untouchable
     reset-prehistory
     set-body
     table
     encapsulate
     include-book))

(defun fmt-ctx (ctx col channel state)

; We print the context in which an error has occurred.  If infix printing is
; being used (infixp = t or :out) then ctx is just the event form itself and we
; print it with evisceration.  Otherwise, we are more efficient in our choice
; of ctx and we interpret it according to its type, to make it convenient to
; construct the more common contexts.  If ctx is nil, we print nothing.  If ctx
; is a symbol, we print it from #\0 via "~x0".  If ctx is a pair whose car is a
; symbol, we print its car and cdr from #\0 and #\1 respectively with "(~x0 ~x1
; ...)".  Otherwise, we print it from #\0 with "~@0".

; We print no other words, spaces or punctuation.  We return the new
; col and state.

  (declare (type (signed-byte 30) col)
           (xargs :guard
                  (and (ctxp ctx)
                       (symbolp channel)
                       (open-output-channel-p channel :character state))))

; The following bit of raw-Lisp code can be useful when observing
; "ACL2 Error in T:".

; #-acl2-loop-only
; (when (eq ctx t) (break))

  (the2s
   (signed-byte 30)
   (cond #+acl2-infix
         ((output-in-infixp state)
          (fmt1 "~p0"
                (list (cons #\0 ctx))
                col channel state
                (evisc-tuple 1 2 nil nil)))
         ((null ctx)
          (mv col state))
         ((symbolp ctx)
          (fmt1 "~x0" (list (cons #\0 ctx)) col channel state nil))
         ((and (consp ctx)
               (symbolp (car ctx)))
          (fmt1 "(~@0~x1 ~x2 ...)"
                (list (cons #\0
                            (if (member-eq (car ctx) *fmt-ctx-spacers*) " " ""))
                      (cons #\1 (car ctx))
                      (cons #\2 (cdr ctx)))
                col channel state nil))
         (t (fmt-abbrev1 "~@0" (list (cons #\0 ctx)) col channel state "")))))

(defun fmt-in-ctx (ctx col channel state)

; We print the phrase " in ctx:  ", if ctx is non-nil, and return
; the new col and state.

  (declare (type (signed-byte 30) col)
           (xargs :guard
                  (and (ctxp ctx)
                       (symbolp channel)
                       (open-output-channel-p channel :character state))))
  (the2s
   (signed-byte 30)
   (cond ((null ctx)
          (fmt1 ":  " nil col channel state nil))
         (t (mv-let (col state)
                    (fmt1 " in " nil col channel state nil)
                    (mv-let (col state)
                            (fmt-ctx ctx col channel state)
                            (fmt1 ":  " nil col channel state nil)))))))

(defun er-soft-off-p1 (summary wrld)

; This function is used by er-soft to determine whether a given error should be
; printed.

  (declare (xargs :guard (and (or (null summary)
                                  (and (stringp summary)
                                       (standard-string-p summary)))
                              (plist-worldp wrld)
                              (standard-string-alistp
                               (table-alist 'inhibit-er-soft-table wrld)))))
  (and summary
       (assoc-string-equal
        summary
        (table-alist 'inhibit-er-soft-table wrld))))

(defun er-soft-off-p (summary state)
  (declare (xargs :stobjs state
                  :guard (and (or (null summary)
                                  (and (stringp summary)
                                       (standard-string-p summary)))
                              (state-p state)
                              (standard-string-alistp
                               (table-alist 'inhibit-er-soft-table
                                            (w state))))))
  (er-soft-off-p1 summary (w state)))

(defun error-fms-channel (hardp ctx summary str alist channel state newlines)

; This function prints the "ACL2 Error" banner and ctx, then the
; user's str and alist, and then two carriage returns.  It returns state.

; Historical Note about ACL2

; Once upon a time we accomplished all this with something like: "ACL2
; Error (in ~xc): ~@s~%~%" and it bound #\c and #\s to ctx and str in
; alist.  That suffers from the fact that it may overwrite the user's
; bindings of #\c and #\s -- unlikely if this error call was generated
; by our er macro.  We rewrote the function this way simply so we
; would not have to remember that some variables are special.

  (cond ((er-soft-off-p summary state)
         state)
        (t
         (flet ((newlines (n channel state)
                          (case n
                            (0 state)
                            (1 (newline channel state))
                            (2 (pprogn (newline channel state)
                                       (newline channel state)))
                            (t (prog2$ (er hard 'error-fms-channel
                                           "Error: The NEWLINES argument of ~
                                            error-fms-channel must be 0, 1, ~
                                            or 2, hence ~x0 is illegal."
                                           n)
                                       state)))))
           (with-output-lock
            (pprogn
             (newlines newlines channel state)
             (mv-let (col state)
               (fmt1 (if hardp
                         "HARD ACL2 ERROR~#0~[~/ [~s1]~]"
                       "ACL2 Error~#0~[~/ [~s1]~]")
                     (list (cons #\0 (if summary 1 0))
                           (cons #\1 summary))
                     0 channel state nil)
               (mv-let (col state)
                 (fmt-in-ctx ctx col channel state)
                 (fmt-abbrev str alist col channel state "")))
             (newlines newlines channel state)))))))

(defun error-fms (hardp ctx summary str alist state)

; See error-fms-channel.  Here we also print extra newlines.

; Keep in sync with error-fms-cw.

  (let ((chan (f-get-global 'standard-co state)))
    (error-fms-channel hardp ctx summary str alist chan state 2)))

#-acl2-loop-only
(defvar *accumulated-warnings* nil)

(defun push-warning-frame (state)
  #-acl2-loop-only
  (setq *accumulated-warnings*
        (cons nil *accumulated-warnings*))
  state)

(defun absorb-frame (lst stk)
  (if (consp stk)
      (cons (union-equal lst (car stk))
            (cdr stk))
    stk))

(defun pop-warning-frame (accum-p state)

; When a "compound" event has a "sub-event" that generates warnings, we want
; the warning strings from the sub-event's summary to appear in the parent
; event's summary.  Accum-p should be nil if and only if the sub-event whose
; warning frame we are popping had its warnings suppressed.

; Starting after Version_4.1, we use the ACL2 oracle to explain warning frames.
; Previously we kept these frames with a state global variable,
; 'accumulated-warnings, rather than in the raw lisp variable,
; *accumulated-warnings*.  But then we introduced warning$-cw1 to support the
; definitions of translate1-cmp and translate-cmp, which do not modify the ACL2
; state.  See the Essay on Context-message Pairs (cmp) for an explanation.
; Since warning$-cw1 uses a wormhole, the warning frames based on a state
; global variable were unavailable when printing warning summaries.

  #+acl2-loop-only
  (declare (ignore accum-p))
  #+acl2-loop-only
  (mv-let (erp val state)
          (read-acl2-oracle state)
          (declare (ignore erp))
          (mv val state))
  #-acl2-loop-only
  (let ((stk *accumulated-warnings*))
    (cond ((consp stk)
           (progn (setq *accumulated-warnings*
                        (if accum-p
                            (absorb-frame (car stk)
                                          (cdr stk))
                          (cdr stk)))
                  (mv (car stk) state)))
          (t (mv (er hard 'pop-warning-frame
                     "The 'accumulated-warnings stack is empty.")
                 state)))))

(defun push-warning (summary state)
  #+acl2-loop-only
  (declare (ignore summary))
  #-acl2-loop-only
  (when (consp *accumulated-warnings*)

; We used to cause an error, shown below, if the above test fails.  But
; WARNINGs are increasingly used by non-events, such as :trans and (thm ...)
; and rather than protect them all with push-warning-frame/pop-warning-frame we
; are just adopting the policy of not pushing warnings if the stack isn't set
; up for them.  Here is the old code.

;            (prog2$ (er hard 'push-warning
;                        "The 'accumulated-warnings stack is empty but we were ~
;                         asked to add ~x0 to the top frame."
;                        summary)
;                     state)

    (setq *accumulated-warnings*
          (cons (add-to-set-equal summary (car *accumulated-warnings*))
                (cdr *accumulated-warnings*))))
  state)

; The ACL2 Record Facilities

; Our record facility gives us the ability to declare "new" types of
; structures which are represented as lists.  If desired the lists
; are tagged with the name of the new record type.  Otherwise they are
; not tagged and are called "cheap" records.

; The expression (DEFREC SHIP (X . Y) NIL) declares SHIP to
; be a tagged (non-cheap) record of two components X and Y.  An
; example concrete SHIP is '(SHIP 2 . 4).  Note that cheapness refers
; only to whether the record is tagged and whether the tag is tested
; upon access and change, not whether the final cdr is used.

; To make a ship:  (MAKE SHIP :X x :Y y) or (MAKE SHIP :Y y :X x).
; To access the Xth component of the ship object obj: (ACCESS SHIP obj :X).
; To change the Xth component to val: (CHANGE SHIP obj :X val).
; Note the use of keywords in these forms.

; It is possible to change several fields at once, e.g.,
; (CHANGE SHIP obj :X val-x :Y val-y).  In general, to cons up a changed
; record one only does the conses necessary.

; The implementation of records is as follows.  DEFREC expands
; into a collection of macro definitions for certain generated function
; symbols.  In the example above we define the macros:

; |Make SHIP record|
; |Access SHIP record field X|
; |Access SHIP record field Y|
; |Change SHIP record fields|

; The macro expression (MAKE SHIP ...) expands to a call of the first
; function.  (ACCESS SHIP ... :X) expands to a call of the second.
; (CHANGE SHIP obj :X val-x :Y val-y) expands to
; (|Change SHIP record fields| obj :X val-x :Y val-y).

; The five new symbols above are defined as macros that further expand
; into raw CAR/CDR nests if the record is cheap and a similar nest
; that first checks the type of the record otherwise.

; In using the record facility I have sometimes pondered which fields I should
; allocate where to maximize access speed.  Other times I have just laid them
; out in an arbitrary fashion.  In any case, the following functions might be
; useful if you are wondering how to lay out a record.  That is, grab the
; following progn and execute it in the full ACL2 system.  (It cannot be
; executed at this point in basis.lisp because it uses functions defined
; elsewhere; it is here only to be easy to find when looking up the comments
; about records.)  Note that it changes the default-defun-mode to :program.  Then
; invoke :sbt n, where n is an integer.

; For example
; ACL2 g>:sbt 5

; The Binary Trees with Five Tips
; 2.400  ((2 . 2) 2 3 . 3)
; 2.600  (1 (3 . 3) 3 . 3)
; 2.800  (1 2 3 4 . 4)

; Sbt will print out all of the interesting binary trees with the
; given number of tips.  The integer appearing at a tip is the number
; of car/cdrs necessary to access that field of a cheap record laid
; out as shown.  That is also the number of conses required to change
; that single field.  The decimal number in the left column is the
; average number of car/cdrs required to access a field, assuming all
; fields are accessed equally often.  The number of trees generated
; grows exponentially with n.  Roughly 100 trees are printed for size
; 10.  Beware!

; The function (analyze-tree x state) is also helpful.  E.g.,

; ACL2 g>(analyze-tree '((type-alist . term) cl-ids rewrittenp
;                          force-flg . rune-or-non-rune)
;                        state)

; Shape:  ((2 . 2) 2 3 4 . 4)
; Field Depths:
; ((TYPE-ALIST . 2)
;  (TERM . 2)
;  (CL-IDS . 2)
;  (REWRITTENP . 3)
;  (FORCE-FLG . 4)
;  (RUNE-OR-NON-RUNE . 4))
; Avg Depth:  2.833

; (progn
;   (program)
;   (defun bump-binary-tree (tree)
;     (cond ((atom tree) (1+ tree))
;           (t (cons (bump-binary-tree (car tree))
;                    (bump-binary-tree (cdr tree))))))
;
;   (defun cons-binary-trees (t1 t2)
;     (cons (bump-binary-tree t1) (bump-binary-tree t2)))
;
;   (defun combine-binary-trees1 (t1 lst2 ans)
;     (cond ((null lst2) ans)
;           (t (combine-binary-trees1 t1 (cdr lst2)
;                                     (cons (cons-binary-trees t1 (car lst2))
;                                           ans)))))
;
;   (defun combine-binary-trees (lst1 lst2 ans)
;     (cond
;      ((null lst1) ans)
;      (t (combine-binary-trees (cdr lst1)
;                               lst2
;                               (combine-binary-trees1 (car lst1) lst2 ans)))))
;
;   (mutual-recursion
;
;    (defun all-binary-trees1 (i n)
;      (cond ((= i 0) nil)
;            (t (revappend (combine-binary-trees (all-binary-trees i)
;                                                (all-binary-trees (- n i))
;                                                nil)
;                          (all-binary-trees1 (1- i) n)))))
;
;    (defun all-binary-trees (n)
;      (cond ((= n 1) (list 0))
;            (t (all-binary-trees1 (floor n 2) n))))
;    )
;
;   (defun total-access-time-binary-tree (x)
;     (cond ((atom x) x)
;           (t (+ (total-access-time-binary-tree (car x))
;                 (total-access-time-binary-tree (cdr x))))))
;
;   (defun total-access-time-binary-tree-lst (lst)
;
; ; Pairs each tree in lst with its total-access-time.
;
;     (cond ((null lst) nil)
;           (t (cons (cons (total-access-time-binary-tree (car lst))
;                          (car lst))
;                    (total-access-time-binary-tree-lst (cdr lst))))))
;
;   (defun show-binary-trees1 (n lst state)
;     (cond ((null lst) state)
;           (t (let* ((tat (floor (* (caar lst) 1000) n))
;                     (d0 (floor tat 1000))
;                     (d1 (- (floor tat 100) (* d0 10)))
;                     (d2 (- (floor tat 10) (+ (* d0 100) (* d1 10))))
;                     (d3 (- tat (+ (* d0 1000) (* d1 100) (* d2 10)))))
;
;                (pprogn
;                 (mv-let (col state)
;                         (fmt1 "~x0.~x1~x2~x3  ~x4~%"
;                               (list (cons #\0 d0)
;                                     (cons #\1 d1)
;                                     (cons #\2 d2)
;                                     (cons #\3 d3)
;                                     (cons #\4 (cdar lst)))
;                               0
;                               *standard-co* state nil)
;                         (declare (ignore col))
;                         state)
;                 (show-binary-trees1 n (cdr lst) state))))))
;
;   (defun show-binary-trees (n state)
;     (let ((lst (reverse
;                 (merge-sort-car->
;                  (total-access-time-binary-tree-lst
;                   (all-binary-trees n))))))
;       (pprogn
;        (fms "The Binary Trees with ~N0 Tips~%"
;             (list (cons #\0 n))
;             *standard-co* state nil)
;        (show-binary-trees1 n lst state))))
;
;   (defun analyze-tree1 (x i)
;     (cond ((atom x) i)
;           (t (cons (analyze-tree1 (car x) (1+ i))
;                    (analyze-tree1 (cdr x) (1+ i))))))
;
;   (defun analyze-tree2 (x i)
;     (cond ((atom x) (list (cons x i)))
;           (t (append (analyze-tree2 (car x) (1+  i))
;                      (analyze-tree2 (cdr x) (1+  i))))))
;
;   (defun analyze-tree3 (x)
;     (cond ((atom x) 1)
;           (t (+ (analyze-tree3 (car x)) (analyze-tree3 (cdr x))))))
;
;   (defun analyze-tree (x state)
;     (let* ((binary-tree (analyze-tree1 x 0))
;            (alist (analyze-tree2 x 0))
;            (n (analyze-tree3 x))
;            (k (total-access-time-binary-tree binary-tree)))
;       (let* ((tat (floor (* k 1000) n))
;              (d0 (floor tat 1000))
;              (d1 (- (floor tat 100) (* d0 10)))
;              (d2 (- (floor tat 10) (+ (* d0 100) (* d1 10))))
;              (d3 (- tat (+ (* d0 1000) (* d1 100) (* d2 10)))))
;         (pprogn
;          (fms "Shape:  ~x0~%Field Depths:  ~x1~%Avg Depth:  ~x2.~x3~x4~x5~%"
;               (list (cons #\0 binary-tree)
;                     (cons #\1 alist)
;                     (cons #\2 d0)
;                     (cons #\3 d1)
;                     (cons #\4 d2)
;                     (cons #\5 d3))
;               *standard-co* state nil)
;          (value :invisible)))))
;
;   (defmacro sbt (n) `(pprogn (show-binary-trees ,n state) (value :invisible))))
;

(defun record-maker-function-name (name)
  (intern-in-package-of-symbol
   (coerce (append (coerce "Make " 'list)
                   (coerce (symbol-name name) 'list)
                   (coerce " record" 'list))
           'string)
   name))

; Record-accessor-function-name is now in axioms.lisp.

(defun record-changer-function-name (name)
  (intern-in-package-of-symbol
   (coerce
    (append (coerce "Change " 'list)
            (coerce (symbol-name name) 'list)
            (coerce " record fields" 'list))
    'string)
   name))

(defmacro make (&rest args)
  (cond ((keyword-value-listp (cdr args))
         (cons (record-maker-function-name (car args)) (cdr args)))
        (t (er hard 'record-error
               "Make was given a non-keyword as a field specifier.  ~
                The offending form is ~x0."
               (cons 'make args)))))

; Access is now in axioms.lisp.

(defmacro change (&rest args)
  (cond ((keyword-value-listp (cddr args))
         (cons (record-changer-function-name (car args)) (cdr args)))
        (t (er hard 'record-error
               "Change was given a non-keyword as a field specifier.  ~
                The offending form is ~x0."
               (cons 'change args)))))

(defun make-record-car-cdrs1 (lst var)
  (cond ((null lst) var)
        (t (list (car lst) (make-record-car-cdrs1 (cdr lst) var)))))

(defun make-record-car-cdrs (field-layout car-cdr-lst)
  (cond ((atom field-layout)
         (cond ((null field-layout) nil)
               (t (list (make-record-car-cdrs1 car-cdr-lst field-layout)))))
        (t (append (make-record-car-cdrs (car field-layout)
                                         (cons 'car car-cdr-lst))
                   (make-record-car-cdrs (cdr field-layout)
                                         (cons 'cdr car-cdr-lst))))))

(defun make-record-accessors (name field-lst car-cdrs cheap)
  (cond ((null field-lst) nil)
        (t
         (cons (cond
                (cheap
                 (list 'defabbrev
                       (record-accessor-function-name name (car field-lst))
                       (list (car field-lst))
                       (car car-cdrs)))
                (t (list 'defabbrev
                         (record-accessor-function-name name (car field-lst))
                         (list (car field-lst))
                         (sublis (list (cons 'name name)
                                       (cons 'x (car field-lst))
                                       (cons 'z (car car-cdrs)))
                                 '(prog2$ (or (and (consp x)
                                                   (eq (car x) (quote name)))
                                              (record-error (quote name) x))
                                          z)))))
               (make-record-accessors name
                                      (cdr field-lst)
                                      (cdr car-cdrs)
                                      cheap)))))

(defun symbol-name-tree-occur (sym sym-tree)

; Sym is a symbol -- in fact, a keyword in proper usage -- and
; sym-tree is a tree of symbols.  We ask whether a symbol with
; the same symbol-name as key occurs in sym-tree.  If so, we return
; that symbol.  Otherwise we return nil.

  (cond ((symbolp sym-tree)
         (cond ((equal (symbol-name sym) (symbol-name sym-tree))
                sym-tree)
               (t nil)))
        ((atom sym-tree)
         nil)
        (t (or (symbol-name-tree-occur sym (car sym-tree))
               (symbol-name-tree-occur sym (cdr sym-tree))))))

(defun some-symbol-name-tree-occur (syms sym-tree)
  (cond ((null syms) nil)
        ((symbol-name-tree-occur (car syms) sym-tree) t)
        (t (some-symbol-name-tree-occur (cdr syms) sym-tree))))

(defun make-record-changer-cons (fields field-layout x)

; Fields is the list of keyword field specifiers that are being
; changed.  Field-layout is the user's layout of the record.  X is the
; name of the variable holding the instance of the record.

  (cond ((not (some-symbol-name-tree-occur fields field-layout))
         x)
        ((atom field-layout)
         field-layout)
        (t
         (list 'cons
               (make-record-changer-cons fields
                                         (car field-layout)
                                         (list 'car x))
               (make-record-changer-cons fields
                                         (cdr field-layout)
                                         (list 'cdr x))))))

(defun make-record-changer-let-bindings (field-layout lst)

; Field-layout is the symbol tree provided by the user describing the
; layout of the fields.  Lst is the keyword/value list in a change
; form.  We want to bind each field name to the corresponding value.
; The only reason we take field-layout as an argument is that we
; don't know from :key which package 'key is in.

  (cond ((null lst) nil)
        (t (let ((var (symbol-name-tree-occur (car lst) field-layout)))
             (cond ((null var)
                    (er hard 'record-error
                        "A make or change form has used ~x0 as though ~
                         it were a legal field specifier in a record ~
                         with the layout ~x1."
                        (car lst)
                        field-layout))
                   (t
                    (cons (list var (cadr lst))
                          (make-record-changer-let-bindings field-layout
                                                            (cddr lst)))))))))

(defun make-record-changer-let (name field-layout cheap rec lst)
  (cond
   (cheap
    (list 'let (cons (list 'record-changer-not-to-be-used-elsewhere rec)
                     (make-record-changer-let-bindings field-layout lst))
          (make-record-changer-cons
           (evens lst)
           field-layout
           'record-changer-not-to-be-used-elsewhere)))
   (t
    (list 'let (cons (list 'record-changer-not-to-be-used-elsewhere rec)
                     (make-record-changer-let-bindings field-layout lst))
          (sublis
           (list (cons 'name name)
                 (cons 'cons-nest
                       (make-record-changer-cons
                        (evens lst)
                        field-layout
                        '(cdr record-changer-not-to-be-used-elsewhere))))
           '(prog2$ (or (and (consp record-changer-not-to-be-used-elsewhere)
                             (eq (car record-changer-not-to-be-used-elsewhere)
                                 (quote name)))
                        (record-error (quote name)
                                      record-changer-not-to-be-used-elsewhere))
                    (cons (quote name) cons-nest)))))))

(defun make-record-changer (name field-layout cheap)
  (list 'defmacro
        (record-changer-function-name name)
        '(&rest args)
        (list 'make-record-changer-let
              (kwote name)
              (kwote field-layout)
              cheap
              '(car args)
              '(cdr args))))

(defun make-record-maker-cons (fields field-layout)

; Fields is the list of keyword field specifiers being initialized in
; a record.  Field-layout is the user's specification of the layout.
; We lay down a cons tree isomorphic to field-layout whose tips are
; either the corresponding tip of field-layout or nil according to
; whether the keyword corresponding to the field-layout tip is in fields.

  (cond ((atom field-layout)
         (cond ((some-symbol-name-tree-occur fields field-layout)

; The above call is a little strange isn't it?  Field-layout is an
; atom, a symbol really, and here we are asking whether any element of
; fields symbol-name-tree-occurs in it.  We're really just exploiting
; some-symbol-name-tree-occur to walk down fields for us taking the
; symbol-name of each element and seeing if it occurs in (i.e., in
; this case, is) the symbol name of field-layout.

                field-layout)
               (t nil)))
        (t
         (list 'cons
               (make-record-maker-cons fields
                                       (car field-layout))
               (make-record-maker-cons fields
                                       (cdr field-layout))))))

(defun make-record-maker-let (name field-layout cheap lst)
  (cond
   (cheap
    (list 'let (make-record-changer-let-bindings field-layout lst)
          (make-record-maker-cons (evens lst)
                                  field-layout)))
   (t
    (list 'let (make-record-changer-let-bindings field-layout lst)
          (list 'cons
                (kwote name)
                (make-record-maker-cons (evens lst)
                                        field-layout))))))

(defun make-record-maker (name field-layout cheap)
  (list 'defmacro
        (record-maker-function-name name)
        '(&rest args)
        (list 'make-record-maker-let
              (kwote name)
              (kwote field-layout)
              cheap
              'args)))

(defun make-record-field-lst (field-layout)
  (cond ((atom field-layout)
         (cond ((null field-layout) nil)
               (t (list field-layout))))
        (t (append (make-record-field-lst (car field-layout))
                   (make-record-field-lst (cdr field-layout))))))

(defun record-maker-recognizer-name (name)

; We use the "WEAK-" prefix in order to avoid name clashes with stronger
; recognizers that one may wish to define.

  (declare (xargs :guard (symbolp name)))
  (intern-in-package-of-symbol
   (concatenate 'string "WEAK-" (symbol-name name) "-P")
   name))

(defun make-record-recognizer-body (field-layout)
  (declare (xargs :guard t))
  (cond
   ((consp field-layout)
    (cond
     ((consp (car field-layout))
      (cond
       ((consp (cdr field-layout))
        `(and (consp x)
              (let ((x (car x)))
                ,(make-record-recognizer-body (car field-layout)))
              (let ((x (cdr x)))
                ,(make-record-recognizer-body (cdr field-layout)))))
       (t
        `(and (consp x)
              (let ((x (car x)))
                ,(make-record-recognizer-body (car field-layout)))))))
     ((consp (cdr field-layout))
      `(and (consp x)
            (let ((x (cdr x)))
              ,(make-record-recognizer-body (cdr field-layout)))))
     (t '(consp x))))
   (t t)))

(defun make-record-recognizer (name field-layout cheap recog-name)
  `(defun ,recog-name (x)
     (declare (xargs :mode :logic :guard t))
     ,(cond (cheap (make-record-recognizer-body field-layout))
            (t `(and (consp x)
                     (eq (car x) ',name)
                     (let ((x (cdr x)))
                       ,(make-record-recognizer-body field-layout)))))))

(defun record-macros (name field-layout cheap recog-name)
  (declare (xargs :guard (or recog-name (symbolp name))))
  (let ((recog-name (or recog-name
                        (record-maker-recognizer-name name))))
    (cons 'progn
          (append
           (make-record-accessors name
                                  (make-record-field-lst field-layout)
                                  (make-record-car-cdrs field-layout
                                                        (if cheap nil '(cdr)))
                                  cheap)
           (list (make-record-changer name field-layout cheap)
                 (make-record-maker name field-layout cheap)
                 (make-record-recognizer name field-layout cheap recog-name))))))

; WARNING: If you change the layout of records, you must change
; certain functions that build them in.  Generally, these functions
; are defined before defrec was defined, but need to access
; components.  See the warning associated with defrec rewrite-constant
; for a list of one group of such functions.  You might also search
; for occurrences of the word defrec prior to this definition of it.

(defmacro defrec (name field-lst cheap &optional recog-name)

; Warning: If when cheap = nil, the car of a record is no longer name, then
; consider changing the definition or use of record-type.

; A recognizer with guard t has is defined using recog-name, if supplied; else,
; by default, its name for (defrec foo ...) is the symbol WEAK-FOO-P, in the
; same package as foo.

  (record-macros name field-lst cheap recog-name))

(defmacro record-type (x)

; X is a non-cheap record, i.e., a record whose defrec has cheap = nil.

  `(car ,x))

; Warning and Observation

; Essay on Inhibited Output and the Illusion of Windows

; The "io" in io?, below, stands for "inhibit output".  Roughly speaking, it
; takes an unevaluated symbolic token denoting a "kind" of output, an output
; shape involving STATE, and a form with the indicated output signature.
; If the "kind" of output is currently inhibited, it returns all nils and the
; current state, e.g., (mv nil state nil) in the case where the output
; shape is something like (mv x state y).  If the kind of output is not
; inhibited, the form is evaluated and its value is returned.

; If form always returned an error triple, this could be said as:
; `(cond ((member-eq ',token (f-get-global 'inhibit-output-lst state))
;         (value nil))
;        (t ,form))
; This whole macro is just a simple way to do optionally inhibited output.

; The introduction of an emacs window-based interface, led us to put a little
; more functionality into this macro.  Each kind of output has a window
; associated with it.  If the kind of output is uninhibited, the io? macro
; sends to *standard-co* certain auxiliary output which causes the
; *standard-co* output by form to be shipped to the designated window.

; The association of windows is accomplished via the constant
; *window-descriptions* below which contains elements of the form (token str
; clear cursor-at-top pop-up), where token is a "kind" of output, str
; identifies the associated window, and the remaining components specify
; options for how output to the window is handled by default.  The io? macro
; provides keyword arguments for overriding these defaults.  If :clear t is
; specified, the window is cleared before the text is written into it,
; otherwise the text is appended to the end.  If :cursor-at-top t is specified,
; the cursor is left at the top of the inserted text, otherwise it is left at
; the bottom of the inserted text.  If :pop-up t is specified, the window is
; raised to the top of the desktop, otherwise the window remains where it was.

; We have purposely avoided trying to suggest that windows are objects in ACL2.
; We have no way to create them or manage them.  We merely ship a sequence of
; characters to *standard-co* and let the host do whatever it does with them.
; Extending ACL2 with some window abstraction is a desirable thing to do.  I
; would like to be able to manipulate windows as ACL2 objects.  But that is
; beyond the scope of the current work whose aim is merely to provide a more
; modern interface to ACL2 without doing too much violence to ACL2's
; applicative nature or to its claim to be Common Lisp.  Those two constraints
; make the introduction of true window objects truly interesting.

; Finally io? allows for the entire io process to be illusory.  This occurs if
; the commentp argument is t.  In this case, the io? form is logically
; equivalent to NIL.  The actual output is performed after opening a wormhole
; to state.

(defun io?-nil-output (lst default-bindings)
  (cond ((null lst) nil)
        (t (cons (cond ((eq (car lst) 'state) 'state)
                       ((cadr (assoc-eq (car lst) default-bindings)))
                       (t nil))
                 (io?-nil-output (cdr lst) default-bindings)))))

(defmacro check-exact-free-vars (ctx vars form)

; A typical use of this macro is (check-free-vars io? vars form) which just
; expands to the translation of form provided all vars occurring freely in form
; are among vars and vice-versa.  The first argument is the name of the calling
; routine, which is used in error reporting.

  (declare (xargs :guard (symbol-listp vars)))
  `(translate-and-test
    (lambda (term)
      (let ((vars ',vars)
            (all-vars (all-vars term)))
        (cond ((not (subsetp-eq all-vars vars))
               (msg "Free vars problem with ~x0:  Variable~#1~[~/s~] ~&1 ~
                     occur~#1~[s~/~] in ~x2 even though not declared."
                    ',ctx
                    (reverse (set-difference-eq all-vars vars))
                    term))
              ((not (subsetp-eq vars all-vars))
               (msg "Free vars problem with ~x0: Variable~#1~[~/s~] ~&1 ~
                     ~#1~[does~/do~] not occur in ~x2 even though declared."
                    ',ctx
                    (reverse (set-difference-eq vars all-vars))
                    term))
              (t t))))
    ,form))

(defun formal-bindings (vars)

; For example, if vars is (ab cd) then return the object
; ((list (quote ab) (list 'quote ab)) (list (quote cd) (list 'quote cd))).

  (if (endp vars)
      nil
    (cons (list 'list
                (list 'quote (car vars))
                (list 'list ''quote (car vars)))
          (formal-bindings (cdr vars)))))

(defrec io-record
  (io-marker . form)
  t)

(defun push-io-record (io-marker form state)
  (declare (xargs :stobjs state
                  :guard (f-boundp-global 'saved-output-reversed state)))
  (f-put-global 'saved-output-reversed
                (cons (make io-record
                            :io-marker io-marker
                            :form form)
                      (f-get-global 'saved-output-reversed state))
                state))

(defun saved-output-token-p (token state)
  (declare (xargs :stobjs state
                  :guard
                  (and (symbolp token)
                       (f-boundp-global 'saved-output-p state)
                       (f-boundp-global 'saved-output-token-lst state)
                       (or (eq (f-get-global 'saved-output-token-lst state)
                               :all)
                           (true-listp (f-get-global 'saved-output-token-lst
                                                     state))))))
  (and (f-get-global 'saved-output-p state)
       (or (eq (f-get-global 'saved-output-token-lst state) :all)
           (member-eq token (f-get-global 'saved-output-token-lst state)))))

(defun io?-wormhole-bindings (i vars)
  (declare (xargs :guard (and (true-listp vars)
                              (natp i))))
  (cond ((endp vars) nil)
        (t (cons (list (car vars)
                       `(nth ,i (@ wormhole-input)))
                 (io?-wormhole-bindings (1+ i) (cdr vars))))))

(defconst *tracked-warning-summaries*

; If you want to prevent duplicate warning messages of another kind (i.e., with
; another summary string, e.g., "use" or "free-vars"), add it to this constant.
; Every element of this list should satisfy both stringp and standard-string-p.
; We use the wormhole data field of the 'COMMENT-WINDOW-IO wormhole to collect
; the explanations of those warnings whose summaries are listed here.  This
; prevents duplicate warnings.  See the note regarding the invariant we
; maintain in the defmacro of io? where we lay down the entry lambda for the
; wormhole.

  '("rewrite-lambda-object"))

(defmacro io? (token commentp shape vars body
                     &key
                     (clear 'nil clear-argp)
                     (cursor-at-top 'nil cursor-at-top-argp)
                     (pop-up 'nil pop-up-argp)
                     (default-bindings 'nil)
                     (chk-translatable 't)
                     (io-marker 'nil))

; Typical use (io? error nil (mv col state) (x y) (fmt ...)), meaning execute
; the fmt statement unless 'error is on 'inhibit-output-lst.  The mv expression
; is the shape of the output produced by the fmt expression, and the list (x y)
; for vars indicates the variables other than state that occur free in that
; expression.  See the comment above, and see the Essay on Saved-output for a
; comment that gives a convenient macro for obtaining the free variables other
; than state that occur free in body.

; Default-bindings is a list of doublets (symbol value).  It is used in order
; to supply a non-nil return value for other than state when io is suppressed.
; For example, fmt returns col and state, as suggested by the third (shape)
; argument below.  Without the :default-bindings, this form would evaluate to
; (mv nil state) if event IO is inhibited.  But there are fixnum declarations
; that require the first return value of fmt to be an integer, and we can
; specify the result in the inhibited case to be (mv 0 state) with the
; following :default-bindings:

; (io? event nil (mv col state) nil (fmt ...) :default-bindings ((col 0)))

; The values in :default-bindings are evaluated, so it would be equivalent to
; replace 0 with (- 4 4), for example.

; Keep argument list in sync with io?@par.

; Chk-translatable is only used when commentp is not nil, to check at translate
; time that the body passes translation relative to the given shape.
; (Otherwise such a check is only made when the wormhole call below is actually
; evaluated.)

; Parallelism blemish: avoid calling io? with commentp = t under
; with-output-lock.  During experimentation, we have ACL2(p) hang in such a
; case, because of the interaction of locks created by wormhole1 and
; with-output-lock.  (So more generally, avoid calling with-wormhole-lock in
; the scope of with-output-lock; the other way around is fine.)

  (declare (xargs :guard (and (symbolp token)
                              (symbol-listp vars)
                              (no-duplicatesp vars)
                              (not (member-eq 'state vars))
                              (assoc-eq token *window-descriptions*))))
  (let* ((associated-window (assoc-eq token *window-descriptions*))
         (expansion
          `(let* ((io?-output-inhibitedp
                   (member-eq ',token
                              (f-get-global 'inhibit-output-lst state)))
                  (io?-alist
                   (and (not io?-output-inhibitedp)
                        (list
                         (cons #\w ,(cadr associated-window))
                         (cons #\c ,(if clear-argp
                                        clear
                                      (caddr associated-window)))
                         (cons #\t ,(if cursor-at-top-argp
                                        cursor-at-top
                                      (cadddr associated-window)))
                         (cons #\p ,(if pop-up-argp
                                        pop-up
                                      (car (cddddr associated-window))))

; Peter Dillinger requested the following binding, so that he could specify a
; window prelude string that distinguishes between, for example, "prove",
; "event", and "summary" output, which with the default string would all just
; show up as window 4.

                         (cons #\k ,(symbol-name token))))))
             (pprogn
              (if (or io?-output-inhibitedp
                      (null (f-get-global 'window-interfacep state)))
                  state
                (mv-let (io?-col state)
                        (fmt1! (f-get-global 'window-interface-prelude state)
                               io?-alist 0 *standard-co* state nil)
                        (declare (ignore io?-col))
                        state))
              ,(let ((body
                      `(check-vars-not-free
                        (io?-output-inhibitedp io?-alist)
                        (check-exact-free-vars io? (state ,@vars) ,body)))
                     (nil-output (if (eq shape 'state)
                                     'state
                                   (cons 'mv (io?-nil-output (cdr shape)
                                                             default-bindings))))
                     (postlude
                      `(mv-let
                        (io?-col state)
                        (if (or io?-output-inhibitedp
                                (null (f-get-global 'window-interfacep state)))
                            (mv 0 state)
                          (fmt1! (f-get-global 'window-interface-postlude state)
                                 io?-alist 0 *standard-co* state nil))
                        (declare (ignore io?-col))
                        (check-vars-not-free
                         (io?-output-inhibitedp io?-alist io?-col)
                         ,shape))))
                 (let ((body (if commentp
                                 `(let ,(io?-wormhole-bindings 0 vars)
                                    ,body)
                               body)))
                   (cond
                    ((eq shape 'state)
                     `(pprogn
                       (if io?-output-inhibitedp state ,body)
                       ,postlude))
                    (t `(mv-let ,(cdr shape)
                                (if io?-output-inhibitedp
                                    ,nil-output
                                  ,body)
                                ,postlude)))))))))
    (cond
     (commentp
      (let ((form
             (cond
              ((eq shape 'state)
               `(pprogn ,expansion (value :q)))
              (t
               `(mv-let ,(cdr shape)
                        ,expansion
                        (declare
                         (ignore ,@(remove1-eq 'state (cdr shape))))
                        (value :q))))))
        `(prog2$
          ,(if chk-translatable
               `(chk-translatable ,body ,shape)
             nil)
          (wormhole 'comment-window-io
                    ',(cond ((or (eq token 'warning)
                                 (eq token 'warning!))

; ``Invariant'' on the Wormhole-Data field of the COMMENT-WINDOW-IO wormhole:

; We'd like to know that the wormhole-data field of the wormhole named
; comment-window-io is an alist and that any key in that alist that is
; string-equal to a member of *tracked-warning-summaries* is bound to a
; true-listp.  We can't actually guarantee that invariant since there is
; nothing to stop the user from invoking wormhole on that name.  We can't just
; prevent the translation of (wormhole 'comment-window-io ...) after boot-strap
; because many books use this macro to lay down such a form.  So instead of
; guaranteeing the invariant we merely check that the data field has the right
; shape when we need it.  The consequence of running this code after the user
; has violated the invariant is merely that some tracked warnings might be
; printed multiple times during a proof.

; Preventing Duplicate Warnings: When the comment window is being used for
; warnings, we assume the supplied input (i.e., the values of the expressions
; in `vars' here which will become the wormhole-input when we manufacture the
; actual wormhole) is exactly as laid down in the macro warning1-form.  We
; check that assumption below as we generate the entry lambda for the wormhole.
; Given that check, the entry lambda below can refer to summary, ctx, alist,
; and str which are, respectively, warning's ``label,'' the context, the fmt
; alist and the fmt string.  Note that the summary here is a string, e.g.,
; "Use" or "use" or "rewrite-lambda-object" and is colloquially called the
; warning's ``label'' or ``kind'' in the documentation.  Let's call ctx, alist,
; and str, collectively as (list ctx alist str), the ``explanation'' of the
; warning.  When the comment window is being used for warnings and the summary
; is string-equal to a member of *tracked-warning-summaries* we keep track of
; the explanations already printed for that summary.  If a warning to be
; printed has a tracked summary and its explanation is already on the alist
; paired with that summary in the wormhole-data we do not print the
; explanation.  We clear the data (of tracked summaries only) in print-summary.
; We spot check that the data field has the right shape according to our
; ``invariant'' above: if the summary is to be tracked, we check that the
; wormhole-data is an alist and that this particular summary string is bound to
; a true-list (so we can do a member-equal check on it).  If these
; ``invariants'' don't hold, we proceed as though the warning isn't to be
; tracked, i.e., we might print the same warning multiple times.

; Here is the entry lambda for warnings:
                             (assert$
                              (equal vars '(summary ctx alist str))
                              '(lambda (whs)
                                 (cond
                                  ((and summary
                                        (member-string-equal
                                         summary
                                         *tracked-warning-summaries*)
                                        (standard-string-alistp
                                         (wormhole-data whs)))
                                   (let ((expln (list ctx alist str))
                                         (entry (or (assoc-string-equal
                                                     summary
                                                     (wormhole-data whs))
                                                    (cons summary nil))))
                                     (cond
                                      ((not (true-listp (cdr entry)))
                                       (set-wormhole-entry-code whs :ENTER))
                                      ((member-equal expln (cdr entry))
; This summary and explanation has already been printed.
                                       (set-wormhole-entry-code whs :SKIP))
                                      (t (make-wormhole-status
                                          whs
                                          :ENTER
; Note: It would, perhaps, be clearer to use put-assoc-string-equal to update
; the entry for this summary label.  But that function hasn't been defined and
; rather than define it we use (the probably faster) put-assoc-equal and
; instead of looking for the current spelling of the summary we look for (car
; entry), the first variation of this summary stored.  E.g., imagine multiple
; "Use" warnings, with different capitalization, e.g., "use", "Use", "USE",
; etc.  The first one stored becomes the ``standard key'' we look for with
; put-assoc-equal.

                                          (put-assoc-equal
                                           (car entry)
                                           (cons expln (cdr entry))
                                           (wormhole-data whs)))))))
                                  (t (set-wormhole-entry-code whs :ENTER))))))
                            (t

; Here is the entry lambda for non-warnings:

                             '(lambda (whs)
                                (set-wormhole-entry-code whs :ENTER))))
                    (list ,@vars)
                    ',form
                    :ld-error-action :return!
                    :ld-verbose nil
                    :ld-pre-eval-print nil
                    :ld-prompt nil))))
     (t `(pprogn
          (cond ((saved-output-token-p ',token state)
                 (push-io-record ,io-marker
                                 (list 'let
                                       (list ,@(formal-bindings vars))
                                       ',expansion)
                                 state))
                (t state))
          ,expansion)))))

#+acl2-par
(defmacro io?@par (token commentp &rest rst)

; This macro is the same as io?, except that it provides the extra property
; that the commentp flag is overridden to use comment-window printing.

; Keep the argument list in sync with io?.

; Parallelism blemish: surround the io? call below with a suitable lock.  Once
; this is done, remove any redundant locks around io?@par calls.

  (declare (ignore commentp))
  `(io? ,token t ,@rst))

(defmacro io?-prove (vars body &rest keyword-args)

; Keep in sync with io?-prove-cw.

  `(io? prove nil state ,vars
        (if (gag-mode) state ,body)
        ,@keyword-args))

(defun output-ignored-p (token state)
  (and (not (saved-output-token-p token state))
       (member-eq token
                  (f-get-global 'inhibit-output-lst state))))

(defun error1 (ctx summary str alist state)

; Warning: Keep this in sync with error1-safe and error1@par.

  (pprogn
   (io? error nil state (alist str ctx summary)
        (error-fms nil ctx summary str alist state))
   (mv t nil state)))

#+acl2-par
(defun error1@par (ctx summary str alist state)

; Keep in sync with error1.  We accept state so that calls to error1 and
; error1@par look the same.

  (declare (ignore state))
  (prog2$
   (our-with-terminal-input ; probably not necessary because of (io? ... t ...)
    (io? error t state (alist str ctx summary)
         (error-fms nil ctx summary str alist state)
         :chk-translatable nil))
   (mv@par t nil state)))

(defun error1-safe (ctx str alist state)

; Warning: Keep this in sync with error1.

; Note: One can rely on this returning a value component of nil.

  (pprogn
   (io? error nil state (alist str ctx)
        (error-fms nil ctx nil str alist state))
   (mv nil nil state)))

(defconst *uninhibited-warning-summaries*
  '("Uncertified"
    "Provisionally certified"
    "Skip-proofs"
    "Defaxioms"
    "Ttags"

; Uncomment the following in order to see invariant-risk warnings during
; regression.
;   "Invariant-risk"

; The above are included because of soundness.  But the following are included
; so that we can see them even when inside include-book, since messages printed
; by missing-compiled-book may assume that such warnings are not inhibited.

    "Compiled file"
    "User-stobjs-modified"))

(defun warning-off-p1 (summary wrld ld-skip-proofsp)

; This function is used by warning$ to determine whether a given warning should
; be printed.  See also warning-disabled-p, which we can use to avoid needless
; computation on behalf of disabled warnings.

  (declare (xargs :guard (and (or (null summary)
                                  (and (stringp summary)
                                       (standard-string-p summary)))
                              (plist-worldp wrld)
                              (standard-string-alistp
                               (table-alist 'inhibit-warnings-table wrld)))))
  (or (and summary
           (assoc-string-equal
            summary
            (table-alist 'inhibit-warnings-table wrld)))

; The above is sufficient to turn off (warning$ "string" ...).  But even when
; the above condition isn't met, we turn off all warnings -- with the exception
; of those related to soundness -- while including a book.

      (and (or (eq ld-skip-proofsp 'include-book)
               (eq ld-skip-proofsp 'include-book-with-locals)
               (eq ld-skip-proofsp 'initialize-acl2))
           (not (and summary
                     (member-string-equal
                      summary
                      *uninhibited-warning-summaries*))))))

(defun warning-off-p (summary state)
  (warning-off-p1 summary (w state) (ld-skip-proofsp state)))

(defrec do-expressionp
  (stobjs-out . with-vars)
  nil)

(defrec state-vars

; Warning: Keep this in sync with default-state-vars.

; Note that do-expressionp is not actually a state global, even though most
; fields do name a state global.  That's OK, as we are careful about this in
; default-state-vars.  Also note that its value is either nil or a
; do-expressionp record.

  (((safe-mode . boot-strap-flg) . (temp-touchable-vars . guard-checking-on))
   .
   ((ld-skip-proofsp . temp-touchable-fns) .
    (parallel-execution-enabled . do-expressionp)))
  nil)

(defmacro default-state-vars
  (state-p &key
           (safe-mode 'nil safe-mode-p)
           (boot-strap-flg 'nil boot-strap-flg-p)
           (temp-touchable-vars 'nil temp-touchable-vars-p)
           (guard-checking-on 't guard-checking-on-p)
           (ld-skip-proofsp 'nil ld-skip-proofsp-p)
           (temp-touchable-fns 'nil temp-touchable-fns-p)
           (parallel-execution-enabled 'nil parallel-execution-enabled-p)
           (do-expressionp ; not a state global, so avoid f-get-global below
            'nil))

; Warning: Keep this in sync with defrec state-vars.

; State-p is t to indicate that we use the current values of the relevant state
; globals.  Otherwise we use the specified defaults, which are supplied above
; for convenience but can be changed there (i.e., in this code) if better
; default values are found.

  (cond ((eq state-p t)
         `(make state-vars
                :safe-mode
                ,(if safe-mode-p
                     safe-mode
                   '(f-get-global 'safe-mode state))
                :boot-strap-flg
                ,(if boot-strap-flg-p
                     boot-strap-flg
                   '(f-get-global 'boot-strap-flg state))
                :temp-touchable-vars
                ,(if temp-touchable-vars-p
                     temp-touchable-vars
                   '(f-get-global 'temp-touchable-vars state))
                :guard-checking-on
                ,(if guard-checking-on-p
                     guard-checking-on
                   '(f-get-global 'guard-checking-on state))
                :ld-skip-proofsp
                ,(if ld-skip-proofsp-p
                     ld-skip-proofsp
                   '(f-get-global 'ld-skip-proofsp state))
                :temp-touchable-fns
                ,(if temp-touchable-fns-p
                     temp-touchable-fns
                   '(f-get-global 'temp-touchable-fns state))
                :parallel-execution-enabled
                ,(if parallel-execution-enabled-p
                     parallel-execution-enabled
                   '(f-get-global 'parallel-execution-enabled state))
                :do-expressionp
                ,do-expressionp))
        (t ; state-p is not t
         `(make state-vars
                :safe-mode ,safe-mode
                :temp-touchable-vars ,temp-touchable-vars
                :guard-checking-on ,guard-checking-on
                :ld-skip-proofsp ,ld-skip-proofsp
                :temp-touchable-fns ,temp-touchable-fns
                :parallel-execution-enabled ,parallel-execution-enabled))))

(defun warning1-body (ctx summary str+ alist state)

; Str+ is either a string or a pair (str . raw-alist), where raw-alist is to be
; used in place of str and the input alist if we are in raw-warning-format
; mode.

  (let ((channel (f-get-global 'proofs-co state)))
    (pprogn
     (if summary
         (push-warning summary state)
       state)
     (cond
      ((f-get-global 'raw-warning-format state)
       (cond ((consp str+)
              (fms "~y0"
                   (list (cons #\0 (list :warning summary
                                         (cons (list :ctx ctx)
                                               (cdr str+)))))
                   channel state nil))
             (t
              (fms "(:WARNING ~x0~t1~y2)~%"
                   (list (cons #\0 summary)
                         (cons #\1 10) ; (length "(:WARNING ")
                         (cons #\2
                               (list (cons :ctx ctx)
                                     (cons :fmt-string str+)
                                     (cons :fmt-alist alist))))
                   channel state nil))))
      (t (let ((str (cond ((consp str+)
                           (assert$ (and (stringp (car str+))
                                         (alistp (cdr str+)))
                                    (car str+)))
                          (t str+))))
           (mv-let
             (col state)
             (fmt "ACL2 Warning~#0~[~/ [~s1]~]"
                  (list (cons #\0 (if summary 1 0))
                        (cons #\1 summary))
                  channel state nil)
             (mv-let (col state)
               (fmt-in-ctx ctx col channel state)
               (fmt-abbrev str alist col channel state "~%~%")))))))))

(defmacro warning1-form (commentp)

; See warning1.

  `(mv-let
    (check-warning-off summary)
    (cond ((consp summary)
           (mv nil (car summary)))
          (t (mv t summary)))
    (cond
     ((and check-warning-off
           ,(if commentp
                '(warning-off-p1 summary
                                 wrld
                                 (access state-vars state-vars
                                         :ld-skip-proofsp))
              '(warning-off-p summary state)))
      ,(if commentp nil 'state))

; Note:  There are two io? expressions below.  They are just alike except
; that the first uses the token WARNING! and the other uses WARNING.  Keep
; them that way!

     ((and summary
           (member-string-equal summary *uninhibited-warning-summaries*))
      (io? WARNING! ,commentp state
           (summary ctx alist str)
           (warning1-body ctx summary str alist state)
           :chk-translatable nil))
     (t (io? WARNING ,commentp state
             (summary ctx alist str)
             (warning1-body ctx summary str alist state)
             :chk-translatable nil)))))

(defun warning1 (ctx summary str alist state)

; This function prints the "ACL2 Warning" banner and ctx, then the
; user's summary, str and alist, and then two carriage returns.

  (warning1-form nil))

(defmacro warning-disabled-p (summary)

; We can use this function to avoid needless computation on behalf of disabled
; warnings.

  (declare (xargs :guard (stringp summary)))
  (let ((tp (if (member-equal summary *uninhibited-warning-summaries*)
                'warning!
              'warning)))
    `(or (output-ignored-p ',tp state)
         (warning-off-p ,summary state))))

(defmacro er-soft (context summary str &rest str-args)
  (let ((alist (make-fmt-bindings *base-10-chars* str-args)))
    (list 'error1 context summary str alist 'state)))

(defmacro er-soft@par (context summary str &rest str-args)
  (let ((alist (make-fmt-bindings *base-10-chars* str-args)))
    (list 'error1@par context summary str alist 'state)))

(defmacro observation1-body (commentp)
  `(io? observation ,commentp state
        (str alist ctx abbrev-p)
        (let ((channel (f-get-global 'proofs-co state)))
          (mv-let
           (col state)
           (fmt "ACL2 Observation" nil channel state nil)
           (mv-let (col state)
                   (fmt-in-ctx ctx col channel state)
                   (cond (abbrev-p
                          (fmt-abbrev str alist col channel state "~|"))
                         ((null abbrev-p)
                          (mv-let (col state)
                                  (fmt1 str alist col channel state nil)
                                  (declare (ignore col))
                                  (newline channel state)))
                         (t
                          (prog2$ (er hard 'observation1
                                      "The abbrev-p (fourth) argument of ~
                                       observation1 must be t or nil, so the ~
                                       value ~x0 is illegal."
                                      abbrev-p)
                                  state))))))
        :chk-translatable nil))

(defun observation1 (ctx str alist abbrev-p state)


; This function prints the "ACL2 Observation" banner and ctx, then the
; user's str and alist, and then a carriage return.

  (observation1-body nil))

(defun observation1-cw (ctx str alist abbrev-p)
  (observation1-body t))

(defmacro observation (&rest args)

; A typical use of this macro might be:
; (observation ctx "5 :REWRITE rules are being stored under name ~x0." name).

  `(cond
    ((or (eq (ld-skip-proofsp state) 'include-book)
         (eq (ld-skip-proofsp state) 'include-book-with-locals)
         (eq (ld-skip-proofsp state) 'initialize-acl2))
     state)
    (t
     (observation1
      ,(car args)
      ,(cadr args)
      ,(make-fmt-bindings '(#\0 #\1 #\2 #\3 #\4
                            #\5 #\6 #\7 #\8 #\9)
                          (cddr args))
      t
      state))))

(defmacro observation-cw (&rest args)

; See observation.  This macro uses wormholes to avoid modifying state, and
; prints even when including books.

  `(observation1-cw
    ,(car args)
    ,(cadr args)
    ,(make-fmt-bindings '(#\0 #\1 #\2 #\3 #\4
                          #\5 #\6 #\7 #\8 #\9)
                        (cddr args))
    t))

; Start stobj support in raw Lisp

(defrec defstobj-field-template
  (((fieldp-name . type) . (init . length-name))
   (accessor-name . updater-name)
   resize-name
   resizable
   . other ; for a hash-table field
   )
  nil)

(defrec defstobj-template
  ((congruent-to . non-memoizable)
   (recognizer . creator)
   field-templates
   inline
   . non-executable)
  nil)

(defun packn1 (lst)
  (declare (xargs :guard (good-atom-listp lst)))
  (cond ((endp lst) nil)
        (t (append (explode-atom (car lst) 10)
                   (packn1 (cdr lst))))))

(defun packn-pos (lst witness)
  (declare (xargs :guard (and (good-atom-listp lst)
                              (symbolp witness))))
  (intern-in-package-of-symbol (coerce (packn1 lst) 'string)
                               witness))

(defun find-first-non-cl-symbol (lst)
  (declare (xargs :guard (good-atom-listp lst)))
  (cond ((endp lst) nil)
        ((and (symbolp (car lst))
              (not (equal (symbol-package-name (car lst))
                          "COMMON-LISP")))
         (car lst))
        (t (find-first-non-cl-symbol (cdr lst)))))

(defun packn (lst)
  (declare (xargs :guard (good-atom-listp lst)))

; This function produces a symbol which is named by concatenating string
; representations of the elements of lst, which may be any good atoms.  The
; package of the output symbol will be the package of the first symbol in the
; input list which is not in the "COMMON-LISP" package, or, if no such symbol
; exists, will be "ACL2".

; We treat the "COMMON-LISP" package as a special exception because in ACL2 we
; limit the usage of symbols in that package, for example by disallowing their
; use as function names.  We therefore prefer not to allow packn to create
; symbols in the "COMMON-LISP" package.  The function packn-pos may be called
; instead when it is desired to specify explicitly a package for the symbol.

  (packn-pos lst (or (find-first-non-cl-symbol lst)
                     'packn)))

(defun pack2 (n1 n2)
  (packn (list n1 n2)))

(defun defstobj-fnname-key2 (type)

; This function provides the value of the key2 argument of defstobj-fnname when
; it is not :top.

  (if (consp type)
      (case (car type)
        (array :array)
        (hash-table :hash-table)
        (stobj-table :stobj-table)
        (t :scalar))
    :scalar))

(defun defstobj-fnname (root key1 key2 renaming-alist)

; Warning: Keep this in sync with stobj-updater-guess-from-accessor.

; This function generates the actual name we will use for a function generated
; by defstobj.  Root and renaming-alist are, respectively, a symbol and an
; alist.  Key1 describes which function name we are to generate and is one of
; :length, :resize, :recognizer, :accessor, :updater, or :creator.  Key2
; describes the ``type'' of root.  It is :top if root is the name of the stobj
; and it is otherwise either :array, :hash-table, :stobj-table, or :scalar (see
; defstobj-fnname-key2).  Note that if renaming-alist is nil, then this
; function returns the ``default'' name used.  If renaming-alist pairs some
; default name with an illegal name, the result is, of course, an illegal name.

  (let* ((default-fnname
           (case key1
             (:recognizer
              (packn-pos (list root "P") root))

; This function can legitimately return nil for key1 values of :length
; and :resize.  We are careful in the assoc-eq call below not to look
; for nil on the renaming-alist.  That check is probably not
; necessary, but we include it for robustness.

             (:length
              (and (eq key2 :array)
                   (packn-pos (list root "-LENGTH") root)))
             (:resize
              (and (eq key2 :array)
                   (packn-pos (list "RESIZE-" root) root)))
             (:accessor
              (case key2
                (:array (packn-pos (list root "I") root))
                ((:hash-table :stobj-table)
                 (packn-pos (list root "-GET") root))
                (otherwise root)))
             (:updater
              (case key2
                (:array (packn-pos (list "UPDATE-" root "I") root))
                ((:hash-table :stobj-table)
                 (packn-pos (list root "-PUT") root))
                (otherwise (packn-pos (list "UPDATE-" root) root))))
             (:creator
              (packn-pos (list "CREATE-" root) root))
             (:boundp
              (and (or (eq key2 :hash-table)
                       (eq key2 :stobj-table))
                   (packn-pos (list root "-BOUNDP") root)))
             (:accessor?
              (and (eq key2 :hash-table)
                   (packn-pos (list root "-GET?") root)))
             (:remove
              (and (or (eq key2 :hash-table)
                       (eq key2 :stobj-table))
                   (packn-pos (list root "-REM") root)))
             (:count
              (and (or (eq key2 :hash-table)
                       (eq key2 :stobj-table))
                   (packn-pos (list root "-COUNT") root)))
             (:clear
              (and (or (eq key2 :hash-table)
                       (eq key2 :stobj-table))
                   (packn-pos (list root "-CLEAR") root)))
             (:init
              (and (or (eq key2 :hash-table)
                       (eq key2 :stobj-table))
                   (packn-pos (list root "-INIT") root)))
             (otherwise
              (er hard 'defstobj-fnname
                  "Implementation error (bad case); please contact the ACL2 ~
                   implementors."))))
         (temp (and default-fnname ; see comment above
                    (assoc-eq default-fnname renaming-alist))))
    (if temp (cadr temp) default-fnname)))

(defun defined-constant (name w)

; Name is a defined-constant if it has been declared with defconst.
; If name is a defined-constant then we can show that it satisfies
; legal-constantp, because when a name is declared as a constant we
; insist that it satisfy the syntactic check.  But there are
; legal-constantps that aren't defined-constants, e.g., any symbol
; that could be (but hasn't yet been) declared as a constant.  We
; check, below, that name is a symbolp just to guard the getprop.

; This function returns the quoted term that is the value of name, if
; name is a constant.  That result is always non-nil (it may be (quote
; nil) of course).

  (and (symbolp name)
       (getpropc name 'const nil w)))

(defun fix-stobj-array-type (type wrld)

; Note: Wrld may be a world or nil.  If wrld is nil and we are in raw Lisp,
; then this function should be called in a context where the symbol-value is
; available for any symbol introduced by a previous defconst event.  Our
; intended use case meets that criterion: evaluation of a defstobj form during
; loading of the compiled file for a book.

  (let* ((max (car (caddr type)))
         (n (cond ((consp wrld)
                   (let ((qc (defined-constant max wrld)))
                     (and qc (unquote qc))))
                  #-acl2-loop-only
                  ((eq wrld nil)
                   (and (symbolp max)
                        (symbol-value max)))
                  (t nil))))
    (cond (n (list (car type)
                   (cadr type)
                   (list n)))
          (t type))))

(defun defstobj-field-templates (field-descriptors renaming wrld)

; Note: Wrld may be a world or nil.  See fix-stobj-array-type.

  (cond
   ((endp field-descriptors) nil)
   (t
    (let* ((field-desc (car field-descriptors))
           (field (if (atom field-desc)
                      field-desc
                    (car field-desc)))
           (type (if (consp field-desc)
                     (or (cadr (assoc-keyword :type (cdr field-desc)))
                         t)
                   t))
           (init (if (consp field-desc)
                     (cadr (assoc-keyword :initially (cdr field-desc)))
                   nil))
           (resizable (if (consp field-desc)
                          (cadr (assoc-keyword :resizable (cdr field-desc)))
                        nil))
           (key2 (defstobj-fnname-key2 type))
           (fieldp-name (defstobj-fnname field :recognizer key2 renaming))
           (accessor-name (defstobj-fnname field :accessor key2 renaming))
           (updater-name (defstobj-fnname field :updater key2 renaming))
           (boundp-name (defstobj-fnname field :boundp key2 renaming))
           (accessor?-name (defstobj-fnname field :accessor? key2
                             renaming))
           (remove-name (defstobj-fnname field :remove key2 renaming))
           (count-name (defstobj-fnname field :count key2 renaming))
           (clear-name (defstobj-fnname field :clear key2 renaming))
           (init-name (defstobj-fnname field :init key2 renaming))
           (resize-name (defstobj-fnname field :resize key2 renaming))
           (length-name (defstobj-fnname field :length key2 renaming)))
      (cons (make defstobj-field-template
                  :fieldp-name fieldp-name
                  :type (cond ((and (consp type)
                                    (eq (car type) 'array))
                               (fix-stobj-array-type type wrld))
                              (t type))
                  :init init
                  :accessor-name accessor-name
                  :updater-name updater-name
                  :length-name length-name
                  :resize-name resize-name
                  :resizable resizable
                  :other
                  (list boundp-name
                        accessor?-name
                        remove-name
                        count-name
                        clear-name
                        init-name))
            (defstobj-field-templates
              (cdr field-descriptors) renaming wrld))))))

(defconst *defstobj-keywords*
  '(:renaming :inline :congruent-to :non-memoizable :non-executable))

; The following function is used to implement a slightly generalized
; form of macro args, namely one in which we can provide an arbitrary
; number of ordinary arguments terminated by an arbitrary number of
; keyword argument pairs.

(defun partition-rest-and-keyword-args1 (x)
  (cond ((endp x) (mv nil nil))
        ((keywordp (car x))
         (mv nil x))
        (t (mv-let (rest keypart)
                   (partition-rest-and-keyword-args1 (cdr x))
                   (mv (cons (car x) rest)
                       keypart)))))

(defun partition-rest-and-keyword-args2 (keypart keys alist)

; We return t if keypart is ill-formed as noted below.  Otherwise, we
; return ((:keyn . vn) ... (:key1 . v1)).

  (cond ((endp keypart) alist)
        ((and (keywordp (car keypart))
              (consp (cdr keypart))
              (not (assoc-eq (car keypart) alist))
              (member (car keypart) keys))
         (partition-rest-and-keyword-args2 (cddr keypart)
                                           keys
                                           (cons (cons (car keypart)
                                                       (cadr keypart))
                                                 alist)))
        (t t)))

(defun partition-rest-and-keyword-args (x keys)

; X is assumed to be a list of the form (a1 ... an :key1 v1 ... :keyk
; vk), where no ai is a keyword.  We return (mv erp rest alist), where
; erp is t iff the keyword section of x is ill-formed.  When erp is
; nil, rest is '(a1 ... an) and alist is '((:key1 . v1) ... (:keyk
; . vk)).

; The keyword section is ill-formed if it contains a non-keyword in an
; even numbered element, if it binds the same keyword more than once,
; or if it binds a keyword other than those listed in keys.

  (mv-let (rest keypart)
          (partition-rest-and-keyword-args1 x)
          (let ((alist (partition-rest-and-keyword-args2 keypart keys nil)))
            (cond
             ((eq alist t) (mv t nil nil))
             (t (mv nil rest alist))))))

(defun defstobj-template (name args wrld)

; Note: Wrld may be a world or nil.  See fix-stobj-array-type.

; We unpack the args to get the renamed field descriptors.  We return a
; defstobj-template with fields (namep create-name fields inline congruent-to),
; where: namep is the name of the recognizer for the single-threaded object;
; create-name is the name of the constructor for the stobj; fields is a list
; corresponding to the field descriptors, but normalized with respect to the
; renaming, types, etc.; inline is t if :inline t was specified in the defstobj
; event, else nil; and congruent-to is the :congruent-to field of the defstobj
; event (default: nil).  A field in fields is of the form (recog-name type init
; accessor-name updater-name length-name resize-name resizable).  The last
; three fields are nil unless type has the form (ARRAY ptype (n)), in which
; case ptype is a primitive type and n is a positive integer.  Init is the evg
; of a constant term, i.e., should be quoted to be a treated as a term.

  (mv-let
   (erp field-descriptors key-alist)
   (partition-rest-and-keyword-args args *defstobj-keywords*)
   (cond
    (erp

; If the defstobj has been admitted, this won't happen.

     (er hard 'defstobj
         "The keyword arguments to the DEFSTOBJ event must appear ~
          after all field descriptors.  The allowed keyword ~
          arguments are ~&0, and these may not be duplicated.  Thus, ~
          ~x1 is ill-formed."
         *defstobj-keywords*
         (list* 'defstobj name args)))
    (t
     (let ((renaming (cdr (assoc-eq :renaming key-alist)))
           (inline (cdr (assoc-eq :inline key-alist)))
           (congruent-to (cdr (assoc-eq :congruent-to key-alist)))
           (non-memoizable (cdr (assoc-eq :non-memoizable key-alist)))
           (non-executable (cdr (assoc-eq :non-executable key-alist))))
       (make defstobj-template
             :recognizer (defstobj-fnname name :recognizer :top renaming)
             :creator (defstobj-fnname name :creator :top renaming)
             :field-templates (defstobj-field-templates
                                field-descriptors renaming wrld)
             :non-memoizable non-memoizable
             :non-executable non-executable
             :inline inline
             :congruent-to congruent-to))))))

(defun simple-array-type (array-etype dimensions)
  (declare (ignore dimensions))
  (cond
   ((eq array-etype t)
    `(simple-vector *))
   ((eq array-etype '*)
    (er hard 'simple-array-type
        "Implementation error: We had thought that * is an invalid type-spec! ~
         ~ Please contact the ACL2 implementors."))
   (t `(simple-array ,array-etype (*)))))

#-acl2-loop-only
(defun-one-output copy-array-aref (a1 a2 i n)
  (declare (type fixnum i n))

; Copy the first n elements of array a1 into array a2, starting with index i,
; and then return a2.  See also copy-array-svref and copy-array-fix-aref.
; Note that this copying does not copy substructures, so in the case that a1 is
; an array of stobjs, if 0 <= i < n then the ith element of a1 will be EQ to
; the ith element of a2 after the copy is complete.

; Addition of (type simple-array a1 a2) to the declare form did not affect the
; output of disassemble in either CCL or SBCL.  So it seems best not to
; consider whether a1 and a2 must be simple-arrays.

  (cond
   ((>= i n) a2)
   (t (setf (aref a2 i)
            (aref a1 i))
      (copy-array-aref a1 a2
                       (the fixnum (1+ i))
                       n))))

#-acl2-loop-only
(defun-one-output copy-array-svref (a1 a2 i n)
  (declare (type fixnum i n)
           (type simple-vector a1 a2))

; This is a variant of copy-array-aref for simple vectors a1 and a2.

  (cond
   ((>= i n) a2)
   (t (setf (svref a2 i)
            (svref a1 i))
      (copy-array-svref a1 a2
                        (the fixnum (1+ i))
                        n))))

#-acl2-loop-only
(defun-one-output copy-array-fix-aref (a1 a2 i n)
  (declare (type fixnum i n)
           (type (simple-array fixnum (*)) a1 a2))

; This is a variant of copy-array-aref for arrays of fixnums a1 and a2.  We
; need this special version to avoid fixnum boxing in GCL during resizing.

  (cond
   ((>= i n) a2)
   (t (setf (aref a2 i)
            (aref a1 i))
      (copy-array-fix-aref a1 a2
                           (the fixnum (1+ i))
                           n))))

; In raw Lisp, the live version of state is held in the constant
; *the-live-state* (whose value is actually just a symbol because we don't
; really represent the live state as an object).  But what is the live version
; of a user-defined stobj?  See the raw lisp variable *user-stobj-alist*.

(defmacro live-stobjp (name)

; Note that unlike the raw Lisp representation of a stobj, no ordinary ACL2
; object is a vector, unless it is a string; nor is any ordinary ACL2 object a
; hash table (unlike the raw Lisp representation of a single-field stobj whose
; field is a hash table).

  `(or (and (typep ,name 'vector)
            (not (stringp ,name)))
       (typep ,name 'hash-table)))

(defun absstobj-name (name type)

; Warning: The (absstobj-name name :CREATOR) should equal (defstobj-fnname name
; :CREATOR :TOP nil), because of the use of the latter in
; parse-with-local-stobj.

  (declare (type symbol name type))
  (mv-let (prefix suffix)
          (case type
            (:A (mv nil "$A")) ; abstract
            (:C (mv nil "$C")) ; concrete (really, foundation)
            (:CREATOR (mv "CREATE-" nil))
            (:RECOGNIZER (mv nil "P"))
            (:RECOGNIZER-LOGIC (mv nil "$AP"))
            (:RECOGNIZER-EXEC (mv nil "$CP"))
            (:CORR-FN (mv nil "$CORR"))
            (:CORRESPONDENCE (mv nil "{CORRESPONDENCE}"))
            (:PRESERVED (mv nil "{PRESERVED}"))
            (:GUARD-THM (mv nil "{GUARD-THM}"))
            (otherwise (mv (er hard 'absstobj-name
                               "Unrecognized type, ~x0."
                               type)
                           nil)))
          (let* ((s (symbol-name name))
                 (s (if prefix (concatenate 'string prefix s) s))
                 (s (if suffix (concatenate 'string s suffix) s)))
            (intern-in-package-of-symbol s name))))

(defrec defstobj-redundant-raw-lisp-discriminator-value

; This record is used both for defstobj and defabsstobj events.

; The first field, :event, completely determines the other fields.  We store
; those simply for convenience, as per the comments below.  At the time of this
; writing (6/14/2020), none of the accesses needs to be efficient; if that
; changes then we can rearrange the fields.

  (event
   creator             ; helpful for get-stobj-creator
   congruent-stobj-rep ; helpful for congruent-stobj-rep-raw
   non-memoizable      ; helpful for non-memoizable-stobj-raw
   non-executable)     ; helpful for add-trip; nil in defabsstobj case
  nil)

(defrec stobj-property
  ((recognizer . creator)
   names ; accessors and updaters
   . live-var)
  nil)

(defun get-stobj-creator (stobj wrld)

; This function assumes that wrld is an ACL2 logical world, although wrld may
; be nil when we call this in raw Lisp.

; If stobj is a stobj name, return the name of its creator; else nil.

  (cond ((eq stobj 'state) 'state-p)
        ((not (symbolp stobj)) nil)
        (wrld (let ((prop (getpropc stobj 'stobj nil wrld)))
                (and prop
                     (access stobj-property prop :creator))))
        (t
         #-acl2-loop-only
         (let ((d (get (the-live-var stobj)
                       'redundant-raw-lisp-discriminator)))
           (cond ((member-eq (car d) '(defstobj defabsstobj))
                  (access defstobj-redundant-raw-lisp-discriminator-value
                          (cdr d)
                          :creator))
                 (t nil)))
         #+acl2-loop-only
         (er hard 'stobj-creator
             "Implementation error: The call ~x0 is illegal, because ~
              get-stobj-creator must not be called inside the ACL2 loop (as ~
              is the case here) with wrld = nil."
             `(get-stobj-creator ,stobj nil)))))

(defmacro the$ (type val)
  (cond ((eq type t)
         val)
        (t `(the ,type ,val))))

#-acl2-loop-only
(defun make-hash-table-with-defaults (test size rehash-size rehash-threshold)

; We leave it to the underlying Lisp implementation to provide the size,
; rehash-size, and rehash-threshold in place of nil.  The test is required to
; be non-nil, and in fact, is required to have value EQ, EQL, HONS-EQUAL, or
; EQUAL.  Note that stobj hash tables with test HONS-EQUAL are actually EQL
; hash tables in the HONS version of ACL2.

; In CCL the relevant defaults appear to be:
; (:SIZE 60 :REHASH-SIZE 1.5 :REHASH-THRESHOLD 0.85)

; In SBCL the relevant defaults appear to be:
; (:SIZE 16 :REHASH-SIZE 1.5 :REHASH-THRESHOLD 1.0)

  (apply 'make-hash-table
         `(:test ,(if (eq test 'hons-equal) 'eql test)
           ,@(and size `(:size

; The GCL implementation installed at UT CS on 9/16/2020 does not allow
; hash-tables of size 0.

                         ,(if (= size 0) 1 size)))
           ,@(and rehash-size `(:rehash-size ,(float rehash-size)))
           ,@(and rehash-threshold `(:rehash-threshold ,(float rehash-threshold))))))

(defmacro get-stobj-scalar-field (elt-type fld)

; Warning: Keep this in sync with make-stobj-scalar-field.

; Through Version_8.2, a scalar field of a stobj with non-trivial type was
; represented as a 1-element array of that type.  This presumably had the
; advantage of avoiding fixnum boxing in GCL for types contained in fixnum.  We
; thus preserve this approach for GCL, but for other Lisps (which presumably do
; not do GCL-style boxing) we avoid the extra indirection through the
; one-element array.

  #+gcl
  `(aref (the (simple-array ,elt-type (1))
              ,fld)
         0)
  #-gcl
  `(the ,elt-type ,fld))

(defmacro make-stobj-scalar-field (elt-type init)

; Warning: Keep this in sync with get-stobj-scalar-field.  See the comments
; there.

  #+gcl
  `(make-array$ 1
                :element-type ',elt-type
                :initial-element ',init)
  #-gcl
  `(the ,elt-type ',init))

(mutual-recursion

(defun maybe-contained-in-character (type)
  (cond ((atom type)
         (or (eq type 'character)
             (eq type 'standard-char)

; We probably don't need to consider 'nil, since no element can have that
; type.  But we have decided to be conservative here.

             (eq type 'nil)))
        ((eq (car type) 'and)
         (some-maybe-contained-in-character (cdr type)))
        ((eq (car type) 'member)

; In GCL, an array type whose elements are, for example, of type (member #\a
; #\b #\c) can be a string.

         (character-listp (cdr type)))
        ((eq (car type) 'not)

; Probably every type-spec of the form (not ...) fails to be contained in
; character.  But we are conservative here and only make that conclusion for
; (not x) where x is an atom.

         (consp (cadr type)))
        ((eq (car type) 'satisfies)

; In GCL, an array type whose elements are of type (satisfies character) can be
; a string.  Since the predicate could be an alias for character, or a subtype
; of character, we are conservative here.

         t)
        ((eq (car type) 'or)
         (all-maybe-contained-in-character (cdr type)))
        (t nil)))

(defun some-maybe-contained-in-character (lst)
  (cond ((endp lst) nil)
        (t (or (maybe-contained-in-character (car lst))
               (some-maybe-contained-in-character (cdr lst))))))

(defun all-maybe-contained-in-character (lst)
  (cond ((endp lst) t)
        (t (and (maybe-contained-in-character (car lst))
                (all-maybe-contained-in-character (cdr lst))))))
)

(defun single-field-type-p (type)

; Normally, when a stobj has a single field which is either an array or a hash
; table, the "backbone" of the stobj is omitted, avoiding one level of
; indirection: in other words, the stobj *is* its field.  However, in the case
; of an array whose type specifies elements that are characters, that array may
; be a string (depending on the host Lisp and exactly how the type is
; specified), which is problematic since the utility live-stobjp depends on
; live stobjs not being strings.  See community book
; books/system/tests/stobj-issues.lisp.  Here, we check whether we can safely
; give the special "single-field" treatment of avoiding the "backbone", based
; on the type of the single field, returning t only if that is indeed safe.

  (and (consp type)
       (cond ((eq (car type) 'array)
              (not (maybe-contained-in-character (cadr type))))
             ((or (eq (car type) 'hash-table)
                  (eq (car type) 'stobj-table))
              t)
             (t nil))))

#-acl2-loop-only
(defg *current-stobj-gensym-ht*
  (make-hash-table :test 'eq))

#-acl2-loop-only
(defun current-stobj-gensym (name)

; This function returns an interned symbol that is a stand-in for name, to use
; as a hash-table key.  It will be replaced in *current-stobj-gensym-ht*
; whenever we undo a defstobj or defabsstobj for name.  The prefix "current"
; emphasizes that this table associates only currently-defined stobjs with
; has-table keys.  When a stobj is undone then its name is removed as a key
; in *current-stobj-gensym-ht*; see maybe-push-undo-stack.

  (declare (type symbol name))
  (let* ((ht *current-stobj-gensym-ht*)
         (val (gethash name ht)))
    (declare (type hash-table ht))
    (or val
        (if (stobjp name t (w *the-live-state*))
            (setf (gethash name ht)
                  (acl2-gentemp (symbol-name name)))
          (error "Attempted to access a stobj-table entry for ~s,~%which is ~
                  not currently the name of a stobj."
                 name)))))

#-acl2-loop-only
(defun clean-stobj-table (ht)

; Returns the number of keys removed.

  (declare (type hash-table ht))
  (let ((valid-keys nil))
    (maphash (lambda (stobj sym)
               (declare (ignore stobj))
               (push sym valid-keys))
             (the hash-table *current-stobj-gensym-ht*))
    (let ((bad-keys nil))
      (maphash (lambda (sym stobj)
                 (declare (ignore stobj))
                 (when (not (member-eq sym valid-keys))
                   (push sym bad-keys)))
               ht)
      (loop for sym in bad-keys
            do
            (remhash sym ht))
      (length bad-keys))))

(defun defstobj-field-fns-raw-defs (var flush-var inline n field-templates)

; Warning:  See the guard remarks in the Essay on Defstobj Definitions.

  (cond
   ((endp field-templates) nil)
   (t
    (append
     (let* ((field-template (car field-templates))
            (type (access defstobj-field-template field-template :type))
            (init (access defstobj-field-template field-template :init))
            (arrayp (and (consp type) (eq (car type) 'array)))
            (array-etype0 (and arrayp (cadr type)))
            (hashp (and (consp type) (eq (car type) 'hash-table)))
            (stobj-tablep (and (consp type) (eq (car type) 'stobj-table)))
            (hash-test (if hashp
                           (cadr type)
                         (and stobj-tablep 'eq)))
            (single-fieldp

; Warning: Keep this in sync with the binding of single-fieldp in
; defstobj-raw-init.

; We avoid some indirection by arranging that when there is a single field that
; is an array, hash-table, or stobj-table, the stobj is the entire structure.
; If that changes, for example to keep indirection for hash-tables, then
; consider changing the definition of live-stobjp.

             (and (= n 0)
                  (null (cdr field-templates))
                  (single-field-type-p type)))
            (fld (if single-fieldp
                     var
                   `(svref ,var ,n)))
            (stobj-creator (get-stobj-creator (if arrayp array-etype0 type)
                                              nil))
            (scalar-type ; used only when arrayp = hashp = stobj-tablep = nil
             (if stobj-creator t type))
            (array-etype (and arrayp
                              (if stobj-creator

; Stobj-creator is non-nil when array-etype is a stobj.  The real element type,
; then, is simple-array rather than a simple-array-type, so we might say that
; the parent stobj array is not simple.  But we will assume that the advantage
; of having a simple-vector for the parent stobj outweighs the advantage of
; having a simple-vector element type declaration.

                                  t
                                array-etype0)))
            (simple-type (and arrayp
                              (simple-array-type array-etype (caddr type))))
            (array-length (and arrayp (car (caddr type))))
            (vref (and arrayp
                       (if (eq (car simple-type) 'simple-vector)
                           'svref
                         'aref)))
            (accessor-name (access defstobj-field-template
                                   field-template
                                   :accessor-name))
            (updater-name (access defstobj-field-template
                                  field-template
                                  :updater-name))
            (length-name (access defstobj-field-template
                                 field-template
                                 :length-name))
            (resize-name (access defstobj-field-template
                                 field-template
                                 :resize-name))
            (resizable (access defstobj-field-template
                               field-template
                               :resizable))
            (other (access defstobj-field-template
                           field-template
                           :other))
            (boundp-name (nth 0 other))
            (accessor?-name (nth 1 other))
            (remove-name (nth 2 other))
            (count-name (nth 3 other))
            (clear-name (nth 4 other))
            (init-name (nth 5 other)))
       (cond
        ((or hashp stobj-tablep)
         (let ((key (if stobj-tablep
                        '(current-stobj-gensym k)
                      (if (eq hash-test 'hons-equal)
                          '(hons-copy k)
                        'k))))
           `((,accessor-name
              ,@(cond (hashp ; (not stobj-tablep)
                       `((k ,var)
                         ,@(and inline (list *stobj-inline-declare*))
                         (values (gethash ,key (the hash-table ,fld)))))
                      (t
                       `((k ,var
; We use v for the default, since we know that v is not ,var.
                            ,@(and stobj-tablep '(v)))
                         ,@(and inline (list *stobj-inline-declare*))
                         (multiple-value-bind
                          (val boundp)
                          (gethash ,key (the hash-table ,fld))
                          (if boundp val v))))))
             (,updater-name
              (k v ,var)
              ,@(and inline (list *stobj-inline-declare*))
              (progn
                (memoize-flush ,var)
                (setf (gethash ,key (the hash-table ,fld))
                      v)
                ,var))
             (,boundp-name
              (k ,var)
              ,@(and inline (list *stobj-inline-declare*))
              (multiple-value-bind (val boundp)
                                   (gethash ,key (the hash-table ,fld))
                                   (declare (ignore val))
                                   (if boundp t nil)))
             ,@(and hashp ; skip this for a stobj-table
                    `((,accessor?-name
                       (k ,var)
                       ,@(and inline (list *stobj-inline-declare*))
                       (multiple-value-bind (val boundp)
                                            (gethash ,key
                                                     (the hash-table ,fld))
                                            (mv val (if boundp t nil))))))
             (,remove-name
              (k ,var)
              ,@(and inline (list *stobj-inline-declare*))
              (progn
                #-acl2-loop-only
                (memoize-flush ,var)
                (remhash ,key (the hash-table ,fld))
                ,var))
             (,count-name
              (,var)
              ,@(and inline (list *stobj-inline-declare*))
              (progn ,@(and stobj-tablep
                            `((clean-stobj-table
                               (the hash-table ,fld))))
                     (hash-table-count (the hash-table ,fld))))
             (,clear-name
              (,var)
              (progn
                #-acl2-loop-only
                (memoize-flush ,var)
                (clrhash (the hash-table ,fld))
                ,@(and (not single-fieldp)
                       (list var))))
             (,init-name
              (ht-size rehash-size rehash-threshold ,var)
              (progn
                #-acl2-loop-only
                (memoize-flush ,var)
                (setf ,fld
                      (make-hash-table-with-defaults ',hash-test
                                                     ht-size
                                                     rehash-size
                                                     rehash-threshold))
                ,@(and (not single-fieldp)
                       (list var)))))))
        (arrayp
         `((,length-name
            (,var)
            ,@(and inline (list *stobj-inline-declare*))
            ,@(if (not resizable)
                  `((declare (ignore ,var))
                    ,array-length)
                `((the (and fixnum (integer 0 *))
                       (length ,fld)))))
           (,resize-name
            (i ,var)
            ,@(if (not resizable)
                  `((declare (ignore i))
                    (prog2$
                     (er hard ',resize-name
                         "The array field corresponding to accessor ~x0 of ~
                          stobj ~x1 was not declared :resizable t.  ~
                          Therefore, it is illegal to resize this array."
                         ',accessor-name
                         ',var)
                     ,var))
                `((if (not (and (integerp i)
                                (>= i 0)
                                (< i array-dimension-limit)))
                      (hard-error
                       ',resize-name
                       "Attempted array resize failed because the requested ~
                        size ~x0 was not a nonnegative integer less than the ~
                        value of Common Lisp constant array-dimension-limit, ~
                        which is ~x1.  These bounds on array sizes are fixed ~
                        by ACL2."
                       (list (cons #\0 i)
                             (cons #\1 array-dimension-limit)))
                    (let* ((var ,var)
                           (old ,(if single-fieldp
                                     'var
                                   `(svref var ,n)))
                           (min-index (min i (length old)))
                           (new (make-array$ i

; The :initial-element below is probably not necessary in the case
; that we are downsizing the array.  At least, CLtL2 does not make any
; requirements about specifying an :initial-element, even when an
; :element-type is supplied.  However, it seems harmless enough to go
; ahead and specify :initial-element even for downsizing: resizing is
; not expected to be fast, we save a case split here (at the expense
; of this comment!), and besides, we are protecting against the
; possibility that some Common Lisp will fail to respect the spec and
; will cause an error by trying to initialize a fixnum array (say)
; with NILs.

                                             :initial-element
                                             ',init
                                             :element-type
                                             ',array-etype)))
                      (memoize-flush ,flush-var)
                      (prog1 (setf ,(if single-fieldp
                                        'var
                                      `(svref var ,n))
                                   (,(pack2 'copy-array- vref)
                                    old new 0 min-index))
                        ,@(and stobj-creator
                               `((when (< (length old) i)
                                   (loop for j from (length old) to (1- i)
                                         do (setf (svref new j)
                                                  (,stobj-creator)))))))
                      ,@(and (not single-fieldp)
                             '(var)))))))
           (,accessor-name
            (i ,var)
            (declare (type (and fixnum (integer 0 *)) i))
            ,@(and inline (list *stobj-inline-declare*))
            (the$ ,array-etype
                  (,vref (the ,simple-type ,fld)
                         (the (and fixnum (integer 0 *)) i))))
           (,updater-name
            (i v ,var)
            (declare (type (and fixnum (integer 0 *)) i)
                     ,@(and (not (eq array-etype t))
                            `((type ,array-etype v))))
            ,@(and inline (list *stobj-inline-declare*))
            (progn
              (memoize-flush ,flush-var)

; See the long comment below for the updater in the scalar case, about
; supporting *1* functions.

              (setf (,vref ,(if (eq simple-type t)
                                fld
                              `(the ,simple-type ,fld))
                           (the (and fixnum (integer 0 *)) i))
                    (the$ ,array-etype v))
              ,var))))
        ((eq scalar-type t)
         `((,accessor-name (,var)
                           ,@(and inline (list *stobj-inline-declare*))
                           ,fld)
           (,updater-name (v ,var)
                          ,@(and inline (list *stobj-inline-declare*))
                          (progn
                            (memoize-flush ,flush-var)

; For the case of a stobj field, we considered causing an error here since the
; raw Lisp code for stobj-let avoids calling updaters because there is no need:
; updates for fields that are stobjs have already updated destructively.
; However, a raw Lisp updater can be called by a *1* function, say *1*f,
; applied to live stobjs, when guard checking does not pass control to the raw
; Lisp function, f.  Perhaps we could optimize to avoid this, but there is no
; need; this setf is fast and is only called on behalf of executing *1*
; function calls.  See the comment referencing "defstobj-field-fns-raw-defs" in
; community book misc/nested-stobj-tests.lisp.  To see this point in action,
; evaluate the forms under that comment after modifying this definition by
; uncommenting the following line of code.

;                           ,@(when stobj-creator '((break$))) ; see just above

                            (setf ,fld v)
                            ,var))))
        (t
         (assert$
          (not stobj-creator) ; scalar-type is t for stobj-creator
          `((,accessor-name (,var)
                            ,@(and inline (list *stobj-inline-declare*))
                            (the$ ,scalar-type
                                  (get-stobj-scalar-field ,scalar-type ,fld)))
            (,updater-name (v ,var)
                           ,@(and (not (eq scalar-type t))
                                  `((declare (type ,scalar-type v))))
                           ,@(and inline (list *stobj-inline-declare*))
                           (progn
                             (memoize-flush ,flush-var)
                             (setf (get-stobj-scalar-field ,scalar-type ,fld)
                                   (the$ ,scalar-type v))
                             ,var)))))))
     (defstobj-field-fns-raw-defs
       var flush-var inline (1+ n) (cdr field-templates))))))

(defun defstobj-raw-init-fields (field-templates)

; Keep this in sync with defstobj-axiomatic-init-fields.

  (cond
   ((endp field-templates) nil)
   (t (let* ((field-template (car field-templates))
             (type (access defstobj-field-template field-template :type))
             (arrayp (and (consp type) (eq (car type) 'array)))
             (hashp (and (consp type) (eq (car type) 'hash-table)))
             (stobj-tablep (and (consp type) (eq (car type) 'stobj-table)))
             (hash-test (if hashp
                            (cadr type)
                          (and stobj-tablep 'eq)))
             (hash-init-size (if hashp
                                 (caddr type)
                               (and stobj-tablep (cadr type))))
             (array-etype0 (and arrayp (cadr type)))
             (array-size (and arrayp (car (caddr type))))
             (stobj-creator (get-stobj-creator (if arrayp array-etype0 type)
                                               nil))
             (array-etype (and arrayp

; See comment for this binding in defstobj-field-fns-raw-defs.

                               (if stobj-creator
                                   t
                                 array-etype0)))
             (init (access defstobj-field-template field-template :init)))
        (cond
         (arrayp
          (cons (cond (stobj-creator
                       (assert$
                        (null init) ; checked by chk-stobj-field-descriptor
                        (assert$

; We expect array-size to be a natural number, as this is checked by
; chk-stobj-field-descriptor (using fix-stobj-array-type).  It is important
; that array-size not be a Lisp form that references the variable AR, even
; after macroexpasion, in order to avoid capture by the binding of AR below.

                         (natp array-size)
                         `(let ((ar (make-array$ ,array-size

; Do not be tempted to use :initial-element (,stobj-creator) here, because that
; would presumably share structure among all the created stobjs.

                                                 :element-type ',array-etype)))
                            (loop for i from 0 to ,(1- array-size)
                                  do
                                  (setf (svref ar i) (,stobj-creator)))
                            ar))))
                      (t `(make-array$ ,array-size
                                       :element-type ',array-etype
                                       :initial-element ',init)))
                (defstobj-raw-init-fields (cdr field-templates))))
         ((or hashp stobj-tablep)
          (cons `(make-hash-table-with-defaults ',hash-test
                                                ,hash-init-size
                                                nil
                                                nil)
                (defstobj-raw-init-fields (cdr field-templates))))
         ((eq type t)
          (cons (kwote init)
                (defstobj-raw-init-fields (cdr field-templates))))
         (stobj-creator
          (cons `(,stobj-creator)
                (defstobj-raw-init-fields (cdr field-templates))))
         (t (cons `(make-stobj-scalar-field ,type ,init)
                  (defstobj-raw-init-fields (cdr field-templates)))))))))

(defun defstobj-raw-init-setf-forms (var index raw-init-fields acc)
  (cond ((endp raw-init-fields) acc) ; no need to reverse
        (t (defstobj-raw-init-setf-forms
             var
             (1+ index)
             (cdr raw-init-fields)
             (cons `(setf (svref ,var ,index)
                          ,(car raw-init-fields))
                   acc)))))

(defun defstobj-raw-init (template)

; This function generates the initialization code for the live object
; representing the stobj name.

  (let* ((field-templates (access defstobj-template template :field-templates))
         (raw-init-fields (defstobj-raw-init-fields field-templates))
         (len (length field-templates))
         (single-fieldp

; Warning: Keep this binding in sync with the binding of single-fieldp in
; defstobj-field-fns-raw-defs.

          (and (= len 1)
               (single-field-type-p (access defstobj-field-template
                                            (car field-templates)
                                            :type)))))
    (cond
     (single-fieldp `,(car raw-init-fields))
     (t `(cond
          ((< ,len call-arguments-limit)

; This check is necessary because GCL complains when VECTOR is called on more
; than 64 arguments.  Actually, the other code -- where LIST is called instead
; of VECTOR -- is in principle just as problematic when field-templates is at
; least as long as call-arguments-limit.  However, GCL has (through 2015 at
; least) been forgiving when LIST is called with too many arguments (as per
; call-arguments-limit).

           (vector ,@raw-init-fields))
          (t
           (let ((v (make-array$ ,len)))
             ,@(defstobj-raw-init-setf-forms 'v 0 raw-init-fields nil)
             v)))))))

(defun defstobj-component-recognizer-calls (field-templates n var ans)

; Warning:  See the guard remarks in the Essay on Defstobj Definitions.

; Given a list of defstobj-field-template records with n+1 field names -- for
; example regp, pcp, ... -- such that var is some symbol, v, we return a
; corresponding list -- for example ((regp (nth 0 v)) (pcp (nth 1 v)) ...).
; Except, for each field corresponding to a non-resizable array then we also
; include a corresponding length statement in the list.

  (cond ((endp field-templates)
         (reverse ans))
        (t (defstobj-component-recognizer-calls
             (cdr field-templates)
             (+ n 1)
             var
             (let* ((type (access defstobj-field-template
                                  (car field-templates)
                                  :type))
                    (nonresizable-ar (and (consp type)
                                          (eq (car type) 'array)
                                          (not (access defstobj-field-template
                                                       (car field-templates)
                                                       :resizable))))
                    (pred-stmt `(,(access defstobj-field-template
                                          (car field-templates)
                                          :fieldp-name)
                                 (nth ,n ,var))))
               (if nonresizable-ar
                   (list* `(equal (len (nth ,n ,var)) ,(car (caddr type)))
                          pred-stmt
                          ans)
                 (cons pred-stmt ans)))))))

(defun stobjp (x known-stobjs w)

; We recognize whether x is to be treated as a stobj name.  Known-stobjs is a
; list of all such names, or else T, standing for all stobj names in w.  During
; translation, only certain known stobjs in w are considered stobjs, as per the
; user's :stobjs declare xargs.  If you want to know whether x has been defined
; as a stobj in w, use known-stobjs = t.

; Slight abuse permitted: Sometimes known-stobjs will be a list of stobj flags!
; E.g., we might supply (NIL NIL STATE NIL $S) where (STATE $S) is technically
; required.  But we should never ask if NIL is a stobj because we only ask this
; of variable symbols.  But just to make this an ironclad guarantee, we include
; the first conjunct below.

  (declare (xargs :guard (and (plist-worldp w)
                              (or (eq known-stobjs t)
                                  (true-listp known-stobjs)))))
  (and x
       (symbolp x)
       (if (eq known-stobjs t)
           (getpropc x 'stobj nil w)
         (member-eq x known-stobjs))))

(defun translate-stobj-type-to-guard (x var wrld)

; This function is a variant of translate-declaration-to-guard.  Like that
; function, x is an alleged type about the variable symbol var -- think
; (DECLARE (TYPE x ...)) -- and results in an UNTRANSLATED term about var if x
; is seen to be a valid type-spec for ACL2.  Unlike that function, here we
; allow x to be a stobj name, which may be used as a type in a field of another
; stobj (introduced after x).  We return nil if x is not either sort of valid
; type spec.

; Our intended use of this function is in generation of guards for recognizers
; of stobj fields that may themselves be stobjs.  We do not use this however in
; accessors or updaters, where translate-declaration-to-guard suffices: we do
; not want to generate a stobj recognizer since the child stobj is supplied
; explicitly using :stobjs.

  (or (translate-declaration-to-guard x var wrld)
      (let ((prop (and (not (eq x 'state))
                       (symbolp x)
                       (getpropc x 'stobj nil wrld))))
        (and prop
             (list (access stobj-property prop :recognizer)
                   var)))))

(defun defstobj-component-recognizer-axiomatic-defs (name template
                                                          field-templates wrld)

; Warning:  See the guard remarks in the Essay on Defstobj Definitions.

; It is permissible for wrld to be nil, as this merely defeats additional
; checking by translate-declaration-to-guard-gen.

; We return a list of defs (see defstobj-axiomatic-defs) for all the
; recognizers for the single-threaded resource named name with the given
; template.  The answer contains the top-level recognizer as well as the
; definitions of all component recognizers.  The answer contains defs for
; auxiliary functions used in array and hash-table component recognizers.  The
; defs are listed in an order suitable for processing (components first, then
; top-level).

  (cond
   ((endp field-templates)
    (let* ((recog-name (access defstobj-template template :recognizer))
           (field-templates (access defstobj-template template
                                    :field-templates))
           (n (length field-templates)))

; Rockwell Addition: See comment below.

; Note: The recognizer for a stobj must be Boolean!  That is why we
; conclude the AND below with a final T.  The individual field
; recognizers need not be Boolean and sometimes are not!  For example,
; a field with :TYPE (MEMBER e1 ... ek) won't be Boolean, nor with
; certain :TYPE (OR ...) involving MEMBER.  The reason we want the
; stobj recognizer to be Boolean is so that we can replace it by T in
; guard conjectures for functions that have been translated with the
; stobj syntactic restrictions.  See optimize-stobj-recognizers.

      (list `(,recog-name (,name)
                          (declare (xargs :guard t
                                          :verify-guards t))
                          (and (true-listp ,name)
                               (= (length ,name) ,n)
                               ,@(defstobj-component-recognizer-calls
                                   field-templates 0 name nil)
                               t)))))
   (t
    (let ((recog-name (access defstobj-field-template
                              (car field-templates)
                              :fieldp-name))
          (type (access defstobj-field-template
                        (car field-templates)
                        :type)))

; Below we simply append the def or defs for this field to those for
; the rest.  We get two defs for each array field and one def for each
; of the others.

      (cons (cond
             ((and (consp type)
                   (eq (car type) 'array))
              (let ((etype (cadr type)))
                `(,recog-name (x)
                              (declare (xargs :guard t
                                              :verify-guards t))
                              (if (atom x)
                                  (equal x nil)
                                (and ,(translate-stobj-type-to-guard
                                       etype '(car x) wrld)
                                     (,recog-name (cdr x)))))))
             ((and (consp type)
                   (or (eq (car type) 'hash-table)
                       (eq (car type) 'stobj-table)))
              `(,recog-name (x)
                            (declare (xargs :guard t
                                            :verify-guards t)
                                     (ignore x))
                            t))
             (t (let ((type-term (translate-stobj-type-to-guard
                                  type 'x wrld)))

; We might not use x in the type-term and so have to declare it ignorable.

                  `(,recog-name (x)
                                (declare (xargs :guard t
                                                :verify-guards t)
                                         (ignorable x))
                                ,type-term))))
            (defstobj-component-recognizer-axiomatic-defs
              name template (cdr field-templates) wrld))))))

(defun congruent-stobj-rep (name wrld)
  (assert$
   wrld ; use congruent-stobj-rep-raw if wrld is not available
   (or (getpropc name 'congruent-stobj-rep nil wrld)
       name)))

(defun all-but-last (l)
  (declare (xargs :guard (true-listp l) ; and let's verify termination/guards:
                  :mode :logic))
  (cond ((endp l) nil)
        ((endp (cdr l)) nil)
        (t (cons (car l) (all-but-last (cdr l))))))

(defun defstobj-raw-defs (name template congruent-stobj-rep wrld)

; Warning:  See the guard remarks in the Essay on Defstobj Definitions.

; This function generates a list of defs.  Each def is such that
; (defun . def) is a well-formed raw Lisp definition.  The defuns can
; be executed in raw lisp to define the versions of the recognizers,
; accessors, and updaters (and for array fields, length and resize
; functions) that are run when we know the guards are satisfied.  Many
; of these functions anticipate application to the live object itself.

; It is permissible for wrld to be nil, as this merely defeats additional
; checking by translate-declaration-to-guard-gen.  If wrld is nil, then
; congruent-stobj-rep should be the result of calling congruent-stobj-rep on
; name and the world where the corresponding defstobj is executed.  If wrld is
; non-nil, then it should be an ACL2 world and congruent-stobj-rep is
; irrelevant.

; WARNING: If you change the formals of these generated raw defs be
; sure to change the formals of the corresponding axiomatic defs.

  (let* ((recog (access defstobj-template template :recognizer))
         (creator (access defstobj-template template :creator))
         (field-templates (access defstobj-template template :field-templates))
         (inline (access defstobj-template template :inline)))
    (append
     (all-but-last
      (defstobj-component-recognizer-axiomatic-defs name template
        field-templates wrld))
     `((,recog (,name)
               (cond
                ((live-stobjp ,name)
                 t)
                (t (and (true-listp ,name)
                        (= (length ,name) ,(length field-templates))
                        ,@(defstobj-component-recognizer-calls
                            field-templates 0 name nil)))))
       (,creator ()
                 ,(defstobj-raw-init template))
       ,@(defstobj-field-fns-raw-defs
           name
           (cond
            ((access defstobj-template template :non-memoizable)
             nil)
            (wrld (let ((congruent-to (access defstobj-template template
                                              :congruent-to)))
                    (if congruent-to
                        (congruent-stobj-rep congruent-to wrld)
                      name)))
            (t congruent-stobj-rep))
           inline 0 field-templates)))))

(defun defconst-name (name)
  (intern-in-package-of-symbol
   (concatenate 'string "*" (symbol-name name) "*")
   name))

(defun defstobj-defconsts (names index)
  (if (endp names)
      nil
    (cons `(defconst ,(defconst-name (car names)) ,index)
          (defstobj-defconsts (cdr names) (1+ index)))))

(defun strip-accessor-names (field-templates)
  (if (endp field-templates)
      nil
    (cons (access defstobj-field-template (car field-templates)
                  :accessor-name)
          (strip-accessor-names (cdr field-templates)))))

(defun the-live-var (name)

; Through Version_8.2, for a stobj named st, (the-live-var st) was a special
; variable.  However, now the live stobj corresponding to st is stored on the
; raw Lisp alist *user-stobj-alist* under the key st.

; Back when we stored it under the value of the the-live-var, we thought that
; one might wonder why we didn't choose to name this object $s.  Below we
; explain our earlier thinking.  Now that we use only (the-live-var name) only
; to store properties, perhaps we could instead store those properties on name;
; but when we eliminated the special variable in October 2019, that didn't seem
; worthwhile to explore.

; Historical Plaque for Why the Live Var for $S Is Not $S

; [Otherwise] Consider how hard it would then be to define the raw defs
; (below).  $S is the formal parameter, and naturally so since we want
; translate to enforce the rules on single-threadedness.  The raw code
; has to check whether the actual is the live object.  We could hardly
; write (eq $S $S).

  (packn-pos (list "*THE-LIVE-" name "*") name))

(defun standard-co (state)
  (f-get-global 'standard-co state))

#-acl2-loop-only
(defun congruent-stobj-rep-raw (name)
  (assert name)
  (let ((d (get (the-live-var name) 'redundant-raw-lisp-discriminator)))
    (assert (member (car d) '(defstobj defabsstobj)
                    :test #'eq))
    (assert (cdr d))
    (access defstobj-redundant-raw-lisp-discriminator-value
            (cdr d)
            :congruent-stobj-rep)))

#-acl2-loop-only
(defmacro defstobj (&whole event name &rest args)

; Warning: If you change this definition, consider the possibility of making
; corresponding changes to the #-acl2-loop-only definition of defabsstobj.

; This function is run when we evaluate (defstobj name . args) in raw lisp.
; A typical such form is

; (defstobj $st
;   (flag :type t :initially run)
;   (pc   :type (integer 0 255) :initially 128)
;   (mem  :type (array (integer 0 255) (256)) :initially 0))

; Warning: If this event ever generates proof obligations, remove it from the
; list of exceptions in install-event just below its "Comment on irrelevance of
; skip-proofs".

; This function must contend with a problem analogous to the one addressed by
; acl2::defconst in acl2.lisp: the need to avoid re-declaration of the same
; stobj.  We use redundant-raw-lisp-discriminator in much the same way as in
; the raw lisp defmacro of acl2::defconst.

  (let* ((template (defstobj-template name args nil))
         (congruent-to (access defstobj-template template :congruent-to))
         (congruent-stobj-rep (if congruent-to
                                  (congruent-stobj-rep-raw congruent-to)
                                name))
         (creator (access defstobj-template template :creator))
         (non-memoizable (access defstobj-template template :non-memoizable))
         (non-executable (access defstobj-template template :non-executable))
         (init-form (defstobj-raw-init template))
         (the-live-name (the-live-var name)))
    `(progn
       ,@(and (null congruent-to)

; It has occurred to us that this defg form might be avoidable when
; non-memoizable is true, since the purpose of st-lst is probably only to
; support memoize-flush.  However, it seems harmless enough to lay down this
; form even when non-memoizable is true, so we go ahead and do so rather than
; think carefully about avoiding it.

              `((defg ,(st-lst name) nil)))

; Now we lay down the defuns of the recognizers, accessors and updaters as
; generated by defstobj-raw-defs.  The boilerplate below just adds the DEFUN to
; the front of each def generated, preserving the order of the defs as
; generated.  We deal here with the :inline case; note that
; *stobj-inline-declare* was added in defstobj-field-fns-raw-defs.

       ,@(mapcar (function (lambda (def)
                             (if (member-equal *stobj-inline-declare* def)
                                 (cons 'DEFABBREV
                                       (remove-stobj-inline-declare def))
                               (cons 'DEFUN def))))
                 (defstobj-raw-defs name template congruent-stobj-rep nil))
       ,@(defstobj-defconsts
           (strip-accessor-names (access defstobj-template template
                                         :field-templates))
           0)
       (let* ((event ',event)
              (creator ',creator)
              (congruent-stobj-rep ',congruent-stobj-rep)
              (non-memoizable ',non-memoizable)
              (non-executable ',non-executable)
              (old-pair (assoc-eq ',name *user-stobj-alist*))
              (d (and (or old-pair non-executable) ; optimization
                      (get ',the-live-name
                           'redundant-raw-lisp-discriminator)))
              (ok-p (and (consp d)
                         (eq (car d) 'defstobj)
                         (equal (access
                                 defstobj-redundant-raw-lisp-discriminator-value
                                 (cdr d)
                                 :event)
                                event))))
         (cond
          (ok-p ',name)
          ((and old-pair (not (raw-mode-p *the-live-state*)))

; If the old stobj was non-executable, then it should be OK to redeclare it
; since there is no issue about what to do with the old value (there isn't
; one).

           (interface-er
            "Illegal attempt to redeclare the single-threaded object ~s0."
            ',name))
          (t
           (setf (get ',the-live-name 'redundant-raw-lisp-discriminator)
                 (cons 'defstobj
                       (make defstobj-redundant-raw-lisp-discriminator-value
                             :event event
                             :creator creator
                             :congruent-stobj-rep congruent-stobj-rep
                             :non-memoizable non-memoizable
                             :non-executable non-executable)))
           (cond (old-pair ; hence raw-mode
                  (fms "Note:  Redefining and ~@0 stobj ~x1 in ~
                        raw mode.~%"
                       (list (cons #\0 (if non-executable
                                           "removing executability of"
                                         "reinitializing"))
                             (cons #\1 ',name))
                       (standard-co *the-live-state*) *the-live-state* nil)
                  (if non-executable
                      (assert$
                       (not (member-eq ',name *non-executable-user-stobj-lst*))
                       (setq *user-stobj-alist*
                             (remove1-assoc-eq ',name *user-stobj-alist*)))
                    (setf (cdr old-pair) ,init-form)))
                 (non-executable
                  (pushnew ',name *non-executable-user-stobj-lst*))
                 (t
                  (setq *user-stobj-alist* ; update-user-stobj-alist
                        (cons (cons ',name ,init-form)
                              *user-stobj-alist*))))
           ',name))))))

; End of stobj support in raw lisp

(defrec ld-history-entry
; This form conceptually belongs with other forms pertaining to ld-history in
; ld.lisp.  But we use this in initialize-state-globals below.
  ((input error-flg)
   stobjs-out/value . user-data)
  nil)

; We need to have state globals bound for prin1$ etc. to work, because of calls
; of with-print-controls.  We may also need the dolist form below for tracing,
; which uses current-package for printing and current-acl2-world for
; current-acl2-world suppression.  State globals such as 'compiler-enabled,
; whose value depends on the host Common Lisp implementation, are initialized
; here rather than in *initial-global-table*, so that the value of any defconst
; (such as *initial-global-table*) is independent of the host Common Lisp
; implementation.  That is important to avoid trivial soundness bugs based on
; variance of a defconst value from one underlying Lisp to another.

#-acl2-loop-only
(initialize-state-globals)

; Local stobj support

(defun parse-with-local-stobj (x)

; x is a with-local-stobj form.  We return (mv erp stobj-name mv-let-form
; creator-name).

  (case-match x
    ((st
      ('mv-let . mv-let-body))
     (cond ((symbolp st)
            (mv nil st (cons 'mv-let mv-let-body)
                (defstobj-fnname st :creator :top nil)))
           (t (mv t nil nil nil))))
    ((st
      ('mv-let . mv-let-body)
      creator)
     (mv nil st (cons 'mv-let mv-let-body) creator))
    (& (mv t nil nil nil))))

#-acl2-loop-only
(defun-one-output mv-let-for-with-local-stobj (mv-let-form st creator flet-fns
                                                           w program-p)

; If w is not nil, then it is the current ACL2 world and we are to oneify the
; appropriate subforms with the indicated program-p argument.  If w is nil,
; then program-p is irrelevant.

; It was tempting to have an acl2-loop-only version of the body below as well,
; which would omit the binding of the live var.  But if someone were to
; verify-termination of this function, we could presumably prove nil using the
; discrepancy between the two versions.  So we take the attitude that
; with-local-stobj is a special form, like let, that is not defined.

; In the case that st is STATE, this form does not take responsibility for
; restoring state, for example by restoring values of state global variables
; and by closing channels that may have been created during evaluation of the
; producer form.  A with-local-state form thus needs to take responsibility for
; restoring state; see for example the definition of channel-to-string.

  (let ((producer (caddr mv-let-form))
        (rest (cdddr mv-let-form)))
    `(mv-let ,(cadr mv-let-form)
             (let* (,@(and (not (eq st 'state))
                           `((,st (,creator))))
                    ,@(cond ((eq st 'state)
                             '((*inside-with-local-state* t)
                               (*wormholep*

; We are in a local state, so it is irrelevant whether or not we are in a
; wormhole, since (conceptually at least) the local state will be thrown away
; after making changes to it.

                                nil)
                               (*file-clock* *file-clock*)
                               (*t-stack* *t-stack*)
                               (*t-stack-length* *t-stack-length*)
                               (*32-bit-integer-stack* *32-bit-integer-stack*)
                               (*32-bit-integer-stack-length*
                                *32-bit-integer-stack-length*)))))
               ,(let ((p (if w
                             (oneify producer flet-fns w program-p)
                           producer)))
                  (if (eq st 'state)
                      `(if (f-get-global 'parallel-execution-enabled
                                         *the-live-state*)
                           (with-local-state-lock ,p)
                         ,p)
                    p)))
             (declare (ignore ,st))
             ,@(if w
                   (if (cdr rest) ; rest is ((declare (ignore ...)) body)
                       (list (car rest)
                             (oneify (cadr rest) flet-fns w program-p))
                     (list (oneify (car rest) flet-fns w program-p)))
                 rest))))

#-acl2-loop-only ; see the comment in mv-let-for-with-local-stobj
(defmacro with-local-stobj (&rest args)

; See books/system/tests/local-stobj.lisp for some tests.

  (mv-let (erp st mv-let-form creator)
          (parse-with-local-stobj args)
          (if (or erp
                  (not (and (true-listp mv-let-form)
                            (<= 3 (length mv-let-form)))))
              (er hard 'with-local-stobj
                  "Macroexpansion of a with-local-stobj call caused an error. ~
                   See :DOC with-local-stobj.")
            (mv-let-for-with-local-stobj mv-let-form st creator nil nil nil))))

; The following definitions were moved here from other-events.lisp so that it
; is included in the toothbrush.

(defun parse-version (version)

; Version is an ACL2 version string, as in state global 'acl2-version.  We
; return (mv major minor incrl rest), where either major is nil, indicating an
; ill-formed version; or else major, minor, and incrl are natural numbers
; indicating the major, minor, and incrl version, and rest is the part of the
; string starting with #\(, if any.  For example,
; (parse-version "ACL2 Version 2.10") is (mv 2 10 0 "") and
; (parse-version "ACL2 Version 2.10.1(r)") is (mv 2 10 1 "(r)").

  (declare (xargs :guard (stringp version)))
  (let* ((root "ACL2 Version")
         (pos0 (if (and (stringp version)
                        (<= 13 (length version))
                        (equal (subseq version 0 12) root)
                        (or (eql (char version 12) #\Space)
                            (eql (char version 12) #\_)))
                   13
                 nil))
         (pos-lparen (position #\( version))
         (end0 (or pos-lparen
                   (length version)))
         (rest (subseq version end0 (length version)))
         (from-pos0 (and pos0 (subseq version pos0 end0)))
         (pos1-from-pos0 (and pos0 (position #\. from-pos0)))
         (pos1 (and pos1-from-pos0 (+ pos0 pos1-from-pos0)))
         (major (and pos1 (decimal-string-to-number
                           (subseq version pos0 pos1)
                           (- pos1 pos0) 0)))
         (from-pos1 (and pos1 (subseq version (1+ pos1) end0)))
         (pos2-from-pos1 (and pos1 (position #\. from-pos1)))
         (pos2 (if pos2-from-pos1
                   (+ (1+ pos1) pos2-from-pos1)
                 (and pos1 end0)))
         (minor (and pos2 (decimal-string-to-number
                           (subseq version (1+ pos1) pos2)
                           (1- (- pos2 pos1)) 0)))
         (incrl (if (and pos2 (< pos2 end0))
                    (decimal-string-to-number
                     (subseq version (1+ pos2) end0)
                     (1- (- end0 pos2))
                     0)
                  0)))
    (mv major minor incrl rest)))

(defun pcd2 (n channel state)
  (declare (xargs :guard (integerp n)))
  (cond ((< n 10)
         (pprogn (princ$ "0" channel state)
                 (princ$ n channel state)))
        (t (princ$ n channel state))))

(defun power-rep (n b)
  (if (< n b)
      (list n)
    (cons (rem n b)
          (power-rep (floor n b) b))))

(defun decode-idate (n)
  (let ((tuple (power-rep n 100)))
    (cond
     ((< (len tuple) 6)
      (er hard 'decode-idate
          "Idates are supposed to decode to a list of at least length six ~
           but ~x0 decoded to ~x1."
          n tuple))
     ((equal (len tuple) 6) tuple)
     (t

; In this case, tuple is (secs mins hrs day month yr1 yr2 ...) where 0
; <= yri < 100 and (yr1 yr2 ...) represents a big number, yr, in base
; 100.  Yr is the number of years since 1900.

        (let ((secs (nth 0 tuple))
              (mins (nth 1 tuple))
              (hrs  (nth 2 tuple))
              (day  (nth 3 tuple))
              (mo   (nth 4 tuple))
              (yr (power-eval (cdr (cddddr tuple)) 100)))
          (list secs mins hrs day mo yr))))))

(defun print-idate (n channel state)
  (let* ((x (decode-idate n))
         (sec (car x))
         (minimum (cadr x))
         (hrs (caddr x))
         (day (cadddr x))
         (mo (car (cddddr x)))
         (yr (cadr (cddddr x))))  ; yr = years since 1900.  It is possible
                                  ; that yr > 99!
    (pprogn
     (princ$ (nth (1- mo)
              '(|January| |February| |March| |April| |May|
                |June| |July| |August| |September|
                |October| |November| |December|))
             channel state)
     (princ$ #\Space channel state)
     (princ$ day channel state)
     (princ$ "," channel state)
     (princ$ #\Space channel state)
     (princ$ (+ 1900 yr) channel state)
     (princ$ "  " channel state)
     (pcd2 hrs channel state)
     (princ$ ":" channel state)
     (pcd2 minimum channel state)
     (princ$ ":" channel state)
     (pcd2 sec channel state)
     state)))

; This definition was originally in acl2-init.lisp, but cmulisp warned that
; *open-output-channel-key*, print-idate, and idate were undefined.
#-acl2-loop-only
(defun saved-build-date-string ()
  (with-output-to-string
   (str)
   (setf (get 'tmp-channel *open-output-channel-key*)
         str)
   (print-idate (idate)
                'tmp-channel
                *the-live-state*)
   (remprop 'tmp-channel *open-output-channel-key*)
   str))

; Quitting

(defun good-bye-fn (status)
  (declare (xargs :mode :logic :guard t))
  #-acl2-loop-only
  (exit-lisp (ifix status))
  status)

(defmacro good-bye (&optional (status '0))
  `(good-bye-fn ,status))

(defmacro exit (&optional (status '0))
  `(good-bye-fn ,status))

(defmacro quit (&optional (status '0))
  `(good-bye-fn ,status))

; Saving an Executable Image

#-acl2-loop-only
(defparameter *initial-cbd* nil)

#-acl2-loop-only
(defvar *return-from-lp* nil)

#-acl2-loop-only
(defvar *lp-init-forms* nil)

(defun expand-tilde-to-user-home-dir (str os ctx state)

; Note that character `~' need not get special treatment by Windows.  See
; comment just above error message below, and see absolute-pathname-string-p.

  (cond ((or (equal str "~")
             (and (< 1 (length str))
                  (eql (char str 0) #\~)
                  (eql (char str 1) #\/)))
         (let ((user-home-dir (f-get-global 'user-home-dir state)))
           (cond
            (user-home-dir
             (concatenate 'string
                          user-home-dir
                          (subseq str 1 (length str))))
            (t

; On Linux or Mac OS, it is surprising to find that user-home-dir is nil.  (See
; the definition of lp to see how it is set.)  But on Windows, it seems that
; this could be the case, say outside an environment like Cygwin, MSYS, or
; MinGW.

             (let ((certify-book-info (f-get-global 'certify-book-info state)))
               (prog2$ (and (or certify-book-info
                                (not (eq os :mswindows)))
                            (er hard ctx
                                "The use of ~~/ for the user home directory ~
                                 in filenames is not supported ~@0."
                                (if certify-book-info
                                    "inside books being certified"
                                  "for this host Common Lisp")))
                       str))))))
        (t str)))

(defun save-exec-fn (exec-filename extra-startup-string host-lisp-args
                                   toplevel-args inert-args return-from-lp
                                   init-forms)

  #-acl2-loop-only
  (progn

    (when (not (our-probe-file (directory-namestring exec-filename)))

; Without this check, CCL will create a directory for us; yet SBCL will not.
; We prefer consistent behavior across all Lisps.  Here we choose to require
; the directory to exist already, to prevent users from creating directories
; they don't want by mistake.

      (error "~s is unable to save to file ~s, because its directory does not ~
              exist."
             'save-exec exec-filename))

; Parallelism blemish: it may be a good idea to reset the parallelism variables
; in all #+acl2-par compilations before saving the image.

    (when (and init-forms return-from-lp)

; For each of return-from-lp and init-forms, a non-nil value takes us through a
; different branch of LP.  Rather than support the use of both, we cause an
; error.

      (er hard 'save-exec
          "The use of non-nil values for both :init-forms and :return-from-lp ~
           is not supported for save-exec.  Consider using only :init-forms, ~
           with (value :q) as the final form."))
    (setq *return-from-lp* return-from-lp)
    (setq *lp-init-forms* init-forms)
    #-sbcl (when toplevel-args
             (er hard 'save-exec
                 "Keyword argument :toplevel-args is only allowed when the ~
                  host Lisp is SBCL."))
    (if (not (eql *ld-level* 0))
        (er hard 'save-exec
            "Please type :q to exit the ACL2 read-eval-print loop and then try ~
             again."))
    (if (equal extra-startup-string "")
        (er hard 'save-exec
            "The extra-startup-string argument of save-exec must be ~x0 or ~
             else a non-empty string."
            nil)
      (setq *saved-string*
            (format
             nil
             "~a~%MODIFICATION NOTICE:~%~%~a~%"
             *saved-string*
             (cond ((null extra-startup-string)
                    "This ACL2 executable was created by saving a session.")
                   (t extra-startup-string)))))
    #-(or gcl cmu sbcl allegro clisp ccl lispworks)
    (er hard 'save-exec
        "Sorry, but save-exec is not implemented for this Common Lisp.")

; The forms just below, before the call of save-exec-raw, are there so that the
; initial (lp) will set the :cbd correctly.

    (f-put-global 'connected-book-directory nil *the-live-state*)
    (setq *initial-cbd* nil)
    (setq *startup-package-name* (package-name *package*))
    (setq *saved-build-date-lst*

; By using setq here for *saved-build-date* instead of a let-binding for
; save-exec-raw, it happens that saving more than once in the same session (for
; Lisps that allow this, such as Allegro CL but not GCL) would result in extra
; "; then ..." strings.  But that seems a minor problem, and avoids having to
; think about the effect of having a let-binding in force above a save of an
; image.

          (cons (saved-build-date-string)
                *saved-build-date-lst*))
    (save-exec-raw (expand-tilde-to-user-home-dir exec-filename
                                                  (os (w *the-live-state*))
                                                  'save-exec
                                                  *the-live-state*)
                   host-lisp-args
                   #+sbcl toplevel-args
                   inert-args))
  #+acl2-loop-only
  (declare (ignore exec-filename extra-startup-string host-lisp-args
                   toplevel-args inert-args return-from-lp init-forms))
  nil ; Won't get to here in GCL and perhaps other lisps
  )

(defmacro save-exec (exec-filename extra-startup-string
                                   &key
                                   host-lisp-args toplevel-args inert-args
                                   return-from-lp init-forms)
  `(save-exec-fn ,exec-filename ,extra-startup-string ,host-lisp-args
                 ,toplevel-args ,inert-args ,return-from-lp ,init-forms))

(defconst *slash-dot-dot*
  (concatenate 'string *directory-separator-string* ".."))

(defconst *length-slash-dot-dot*
  (length *slash-dot-dot*))

(defun find-dot-dot (full-pathname i)

; Termination and even guard-verification are proved in community book
; books/system/extend-pathname.lisp.

  (declare (xargs :guard (and (stringp full-pathname)
                              (natp i)
                              (<= i (length full-pathname)))
                  :measure (nfix (- (length full-pathname) i))))
  (let ((pos (search *slash-dot-dot* full-pathname :start2 i)))
    (and pos
         (let ((pos+3 (+ pos *length-slash-dot-dot*)))
           (cond
            ((or (eql pos+3 (length full-pathname))
                 (eql (char full-pathname pos+3) *directory-separator*))
             pos)
            ((mbt (<= pos+3 (length full-pathname)))
             (find-dot-dot full-pathname pos+3)))))))

(mutual-recursion

; The :measure declarations in this mutual-recursion nest are in support of
; community book books/system/extend-pathname.lisp.  The :guard declarations
; below are intended to be correct, but we won't really know until guards have
; been verified; it seems quite possible that the guards will need to be
; adjusted.

(defun cancel-dot-dots (full-pathname)
  (declare (xargs :guard (stringp full-pathname)
                  :measure (* 2 (length full-pathname))))
  (let ((p (find-dot-dot full-pathname 0)))
    (cond ((and p
                (mbt ; termination help
                 (and (natp p)
                      (stringp full-pathname)
                      (< p (length full-pathname)))))
           (let ((new-p
                  (merge-using-dot-dot
                   (subseq full-pathname 0 p)
                   (subseq full-pathname (1+ p) (length full-pathname)))))
             (and (mbt ; termination help
                   (and (stringp new-p)
                        (< (length new-p) (length full-pathname))))
                  (cancel-dot-dots new-p))))
          (t full-pathname))))

(defun get-parent-directory (p0)

; P is an absolute pathname for a directory, not a file, where p does not end
; in "/".  We return an absolute pathname for its parent directory, not
; including the trailing "/".  See also get-directory-of-file, which is a
; related function for files.

  (declare (xargs :guard (stringp p0)
                  :measure (1+ (* 2 (length p0)))))
  (let* ((p (and (mbt (stringp p0))
                 (cancel-dot-dots p0)))
         (posn (search *directory-separator-string* p :from-end t)))
    (cond
     (posn (subseq p 0 posn))
     (t (er hard? 'get-parent-directory
            "Implementation error!  Unable to get parent directory for ~
             directory ~x0."
            p0)))))

(defun merge-using-dot-dot (p s)

; P is the absolute pathname of a directory without the final "/".  S is a
; pathname (for a file or a directory) that may start with any number of
; sequences "../" and "./".  We want to "cancel" the leading "../"s in s
; against directories at the end of p, and eliminate leading "./"s from s
; (including leading "." if that is all of s).  The result should syntactically
; represent a directory (end with a "/" or "."  or be "") if and only if s
; syntactically represents a directory.

; This code is intended to be simple, not necessarily efficient.

  (declare (xargs :guard (and (stringp p)
                              (stringp s)
                              (not (equal s "")))
                  :measure (+ 1 (* 2 (+ (length p) (length s))))))
  (cond
   ((not (mbt ; termination help
          (and (stringp p)
               (stringp s)
               (not (equal s "")))))
    nil)
   ((equal p "") s)
   ((equal s "..")
    (concatenate 'string
                 (get-parent-directory p)
                 *directory-separator-string*))
   ((equal s ".")
    (concatenate 'string
                 p
                 *directory-separator-string*))
   ((and (>= (length s) 3)
         (eql (char s 0) #\.)
         (eql (char s 1) #\.)
         (eql (char s 2) #\/)
         (mbt (<= (length (get-parent-directory p)) ; termination help
                  (length p))))
    (merge-using-dot-dot (get-parent-directory p)
                         (subseq s 3 (length s))))
   ((and (>= (length s) 2)
         (eql (char s 0) #\.)
         (eql (char s 1) #\/))
    (merge-using-dot-dot p (subseq s 2 (length s))))
   (t
    (concatenate 'string p *directory-separator-string* s))))

)

; Print-object$ etc.

(defun comment-string-p1 (s i end)

; We assume that i points to the start of a line of s.

  (declare (type (unsigned-byte 29) end)
           (xargs :measure (nfix (- end i))
                  :guard (and (natp i)
                              (stringp s)
                              (= end (length s))
                              (<= i end))))
  (cond
   ((not (mbt (and (unsigned-byte-p 29 end)
                   (natp i)
                   (stringp s)
                   (= end (length s))
                   (<= i end))))
    (er hard 'comment-string-p1
        "Guard violation!"))
   (t (let ((j (scan-past-whitespace s i end)))
        (cond
         ((= j end) t)
         ((eql (char s i) #\;)
          (let ((p (search *newline-string* s :start2 j)))
            (or (null p)
                (comment-string-p1 s (1+ p) end))))
         (t nil))))))

(defun comment-string-p (s)
  (declare (xargs :guard t))
  (and (stringp s)
       (let ((len (length s)))
         (and (unsigned-byte-p 29 len)
              (comment-string-p1 s 0 len)))))

(defrec print-control

; The alist maps Lisp variables to values, like the bindings in calls of
; with-print-controls..  So a key might be *PRINT-BASE* but not PRINT-BASE or
; :PRINT-BASE.

  (header . alist)
  nil)

(defconst *print-control-defaults*

; Warning: Keep this in sync with print-control-alistp.

  `((print-base ',(cdr (assoc-eq 'print-base *initial-global-table*))
                set-print-base)
    (print-case ',(cdr (assoc-eq 'print-case *initial-global-table*))
                set-print-case)
    (print-circle ',(cdr (assoc-eq 'print-circle *initial-global-table*))
                  set-print-circle)
    (print-escape ',(cdr (assoc-eq 'print-escape *initial-global-table*))
                  set-print-escape)
    (print-length ',(cdr (assoc-eq 'print-length *initial-global-table*))
                  set-print-length)
    (print-level ',(cdr (assoc-eq 'print-level *initial-global-table*))
                 set-print-level)
    (print-lines ',(cdr (assoc-eq 'print-lines *initial-global-table*))
                 set-print-lines)
    (print-pretty ',(cdr (assoc-eq 'print-pretty *initial-global-table*))
                  set-print-pretty)
    (print-radix ',(cdr (assoc-eq 'print-radix *initial-global-table*))
                  set-print-radix)
    (print-readably ',(cdr (assoc-eq 'print-readably *initial-global-table*))
                    set-print-readably)
    (print-right-margin ',(cdr (assoc-eq 'print-right-margin
                                         *initial-global-table*))
                        set-print-right-margin)))

(defun print-control-alistp (alist)

; Warning: Keep this in sync with *print-control-defaults*.

  (declare (xargs :guard (alistp alist) :mode :logic))
  (cond
   ((endp alist) t)
   ((let ((key (caar alist))
          (val (cdar alist)))
      (case key
        (*print-base* (print-base-p val))
        (*print-case* (member-eq val '(:upcase :downcase)))
        ((*print-length* *print-level* *print-lines* *print-right-margin*)
         (check-null-or-natp val key))
        ((*print-circle* *print-escape* *print-pretty* *print-radix*
                         *print-readably*)
         t)
        (otherwise
         (hard-error 'print-control-p
                     "The symbol ~x0 is not a legal print control variable."
                     (list (cons #\0 key))))))
    (print-control-alistp (cdr alist)))
   (t nil)))

(defconst *raw-print-vars-keys*
  (strip-cars *raw-print-vars-alist*))

(defun alist-keys-subsetp (x keys)
  (declare (xargs :guard (and (alistp x)
                              (symbol-listp keys))))
  (cond ((endp x) t)
        ((member-eq (caar x) keys)
         (alist-keys-subsetp (cdr x) keys))
        (t nil)))

(defun print-control-p (x)
  (declare (xargs :guard t))
  (and (weak-print-control-p x)
       (or (null (access print-control x :header))
           (comment-string-p (access print-control x :header)))
       (alistp (access print-control x :alist))
       (alist-keys-subsetp (access print-control x :alist)
                           *raw-print-vars-keys*)
       (print-control-alistp (access print-control x :alist))))

(defun print-object$-fn (x control channel state-state)

; Wart: We use state-state instead of state because of a bootstrap problem.

; This function is a version of print-object$ that allows specification of the
; serialize-character, which can be nil, #\Y, or #\Z (the normal case).  It
; also allows, if serialize-character is not specified, the specification of a
; header (comment) to print and of print-controls.

; See print-object$ for additional comments.

  (declare (ignorable control)
           (xargs :guard (and (state-p1 state-state)

; We considered placing the following conjunct here.
;   (or (member control '(nil #\Y #\Z))
;       (print-control-p control))

; When trying that, we also added print-object$-fn to
; *system-verify-guards-alist* (together with print-control-p and some of its
; supporting function symbols).  Unfortunately, we ran into problems applying
; verify-termination to print-object$-fn (in books/system/fmx-cw.lisp), because
; it has raw Lisp code.  On further reflection it seemed that we can just do a
; runtime check on print-control-p, which is presumably a cheap check compared
; to printing.

                              (symbolp channel)
                              (open-output-channel-p1 channel
                                                      :object state-state))))
  #-acl2-loop-only
  (when (live-state-p state-state)
    (when *wormholep*

; There is no standard object output channel and hence this channel is
; directed to some unknown user-specified sink and we can't touch it.

      (wormhole-er 'print-object$ (list x channel)))
    (let ((stream (get-output-stream-from-channel channel))
          (controlp (and control
                         (not (characterp control)))))
      (when (and controlp
                 (not (print-control-p control)))
; See comment about this check in the :guard above.
        (er hard 'print-object$-fn
            "Illegal print-control record, ~x0"
            control))

; Note: If you change the following bindings, consider changing the
; corresponding bindings in print-object$.

      (with-print-controls
       (and controlp
            (access print-control control :alist))
       ((*print-circle* (and *print-circle-stream*
                             (f-get-global 'print-circle state-state))))
       (let ((header (if controlp
                         (access print-control control :header)
                       *newline-string*)))
         (when header ; hence (stringp header)
           (princ$ header channel state-state)
           (unless (eql (char header (1- (length header))) #\Newline)
             (terpri stream))))
       (or (let ((serialize-character
                  (and (not controlp)
                       control)))
             (cond (serialize-character
                    (write-char #\# stream)
                    (write-char serialize-character stream)
                    (ser-encode-to-stream x stream)
                    t)))
           (prin1 x stream))
       (force-output stream)))
    (return-from print-object$-fn state-state))
  (let ((entry (cdr (assoc-eq channel (open-output-channels state-state)))))
    (update-open-output-channels
     (add-pair channel
               (cons (car entry)
                     (cons x
                           (cdr entry)))
               (open-output-channels state-state))
     state-state)))

(defun print-object$ (x channel state)

; WARNING: Be sure to use with-output-object-channel-sharing rather than
; calling open-output-channel directly, so that *print-circle-stream* is
; initialized.

; We believe that if in a single Common Lisp session, one prints an object and
; then reads it back in with print-object$ and read-object, one will get back
; an equal object under the assumptions that (a) the package structure has not
; changed between the print and the read and (b) that *package* has the same
; binding.  On a toothbrush, all calls of defpackage will occur before any
; read-objecting or print-object$ing, so the package structure will be the
; same.  It is up to the user to set current-package back to what it was at
; print time if he hopes to read back in the same object.

; Warning: For soundness, we need to avoid using iprinting when writing to
; certificate files.  We do all such writing with print-object$, so we rely on
; print-object$ not to use iprinting.

  (declare (xargs :guard (and (state-p state)

; We might want to modify state-p (actually, state-p1) so that the following
; conjunct is not needed.

                              (symbolp channel)
                              (open-output-channel-p channel
                                                     :object state))))
  (print-object$-fn x (get-serialize-character state) channel state))

(defun print-object$-preserving-case (x channel state)

; Logically, this function is just print-object$.  Is it unsound to identify
; these functions, since they print differently?  We think not, because the
; only way to see what resides in a file is with the various ACL2 reading
; functions, which all use a file-clock.  See the discussion of "deus ex
; machina" in :doc current-package.

  (declare (xargs :guard (and (state-p state)
                              (eq (get-serialize-character state)

; It's not clear that it makes sense to print preserving case when doing
; serialize printing.  If that capability is needed we can address weakening the
; guard to match the guard of print-object$.

                                  nil)
                              (symbolp channel)
                              (open-output-channel-p channel
                                                     :object state))))
  #-acl2-loop-only
  (cond ((live-state-p state)
         (cond
          #+gcl
          ((not (fboundp 'system::set-readtable-case))
           (cerror "Use print-object$ instead"
                   "Sorry, but ~s is not supported in this older version of ~%~
                    GCL (because raw Lisp function ~s is undefined)."
                   'print-object$-preserving-case
                   'system::set-readtable-case))
          (t
           (return-from print-object$-preserving-case
             (let ((*acl2-readtable* (copy-readtable *acl2-readtable*)))
               (set-acl2-readtable-case :preserve)
               (print-object$ x channel state)))))))
  (print-object$ x channel state))

(defmacro print-object$+ (x channel
                            &rest args
                            &key
                            (header 'nil headerp)
                            (serialize-character 'nil serialize-character-p)
                            &allow-other-keys)
  (declare (xargs :guard (keyword-value-listp args)))
  (cond
   ((and serialize-character-p
         (not (eq serialize-character nil))
         (not (equal serialize-character ''nil))
         (cddr args))
    (er hard 'print-object$+
        "It is illegal for a call of ~x0 to specify a value for ~
         :SERIALIZE-CHARACTER other than ~x1 or ~x2 when at least one other ~
         keyword argument is supplied."
        'print-object$+
        nil
        ''nil))
   (t `(print-object$-fn ,x
                         ,(if (and serialize-character-p
                                   (not (eq serialize-character nil))
                                   (not (equal serialize-character ''nil)))
                              serialize-character
                            `(make print-control
                                   :header ,(if headerp
                                                header
                                              *newline-string*)
                                   :alist ,(print-object$+-alist args)))
                         ,channel
                         state))))