More conservative whitespace handling in symex bounds

Include at most one trailing whitespace character in symex bounds. Fix
whitespace regex. Don't eliminate intervening trailing whitespace on
deletion. Some whitespace-related utilities.

symex-primitives-lisp.el

@@ -165,7 +165,7 @@
 (defvar symex--re-blank-line "^[[:space:]]*$"
   "A blank line, either empty or containing only whitespace.")
 
-(defvar symex--re-whitespace "[[:space:]|\n]*"
+(defvar symex--re-whitespace "[[:space:]|\n]+"
   "Whitespace that may extend over many lines.")
 
 (defvar symex--re-symex-line "^[[:space:]]*[^;[:space:]\n]"
@@ -211,6 +211,10 @@
   (cond ((looking-at "\\s(") (forward-list 1) (backward-char 1))
         ((looking-at "\\s)") (forward-char 1) (backward-list 1))))
 
+(defun symex-whitespace-p ()
+  "Check if we're looking at whitespace."
+  (looking-at-p symex--re-whitespace))
+
 (defun symex-comment-line-p ()
   "Check if we're currently at the start of a comment line."
   (save-excursion
@@ -424,8 +428,9 @@ including trailing whitespace at the end of the last symex."
     (let ((endpoint (symex-lisp--get-end-point-helper count)))
       (if include-whitespace
           (progn (goto-char endpoint)
-                 (if (symex--go-to-next-non-whitespace-char)
-                     (1- (point))
+                 (if (and (not (eobp))
+                          (symex-whitespace-p))
+                     (1+ endpoint)
                    endpoint))
         endpoint))))
 
@@ -678,7 +683,7 @@ line."
                              (error nil))
                      (symex--join-to-match symex--re-right))))))))
         ((symex-right-p) (fixup-whitespace)) ; abc <>)
-        (t (symex--join-to-non-whitespace))))
+        (t nil)))
 
 ;;; Utilities
 

symex-utils.el

@@ -71,6 +71,9 @@ the following recipe instead."
 (defvar symex--re-non-whitespace "[^[:space:]\n]"
   "A non-whitespace character.")
 
+(defvar symex--re-non-whitespace-or-newline "[^[:space:]]"
+  "A non-whitespace character.")
+
 (defun symex--go-to-next-non-whitespace-char ()
   "Move point to the next non-whitespace character.
 
@@ -101,6 +104,13 @@ This eliminates whitespace between the original position and the found
 match."
   (symex--join-to-match symex--re-non-whitespace))
 
+(defun symex--join-to-non-whitespace-or-newline ()
+  "Join current position to the next non-whitespace character.
+
+This eliminates whitespace between the original position and the found
+match."
+  (symex--join-to-match symex--re-non-whitespace-or-newline))
+
 ;; `with-undo-collapse` macro, to treat a sequence of operations
 ;; as a single entry in the undo list.
 ;; From: https://emacs.stackexchange.com/questions/7558/collapsing-undo-history/7560#7560