crook

iniquity-plus/env.rkt

@@ -0,0 +1,16 @@
+#lang racket
+(provide lookup ext)
+
+;; Env Variable -> Answer
+(define (lookup env x)
+  (match env
+    ['() 'err]
+    [(cons (list y i) env)
+     (match (symbol=? x y)
+       [#t i]
+       [#f (lookup env x)])]))
+
+;; Env Variable Value -> Value
+(define (ext r x i)
+  (cons (list x i) r))
+

iniquity-plus/interp.rkt

@@ -3,6 +3,7 @@
 (provide interp-env)
 (require "ast.rkt")
 (require "interp-prim.rkt")
+(require "env.rkt")
 
 ;; type Value =
 ;; | Integer
@@ -142,15 +143,3 @@
      (cons (list x y)
            (zip xs ys))]))
 
-;; Env Id -> Value
-(define (lookup r x)
-  (match r
-    [(cons (list y val) r)
-     (if (symbol=? x y)
-         val
-         (lookup r x))]))
-
-;; Env Id Value -> Env
-(define (ext r x v)
-  (cons (list x v) r))
-

knock-plus/env.rkt

@@ -0,0 +1,16 @@
+#lang racket
+(provide lookup ext)
+
+;; Env Variable -> Answer
+(define (lookup env x)
+  (match env
+    ['() 'err]
+    [(cons (list y i) env)
+     (match (symbol=? x y)
+       [#t i]
+       [#f (lookup env x)])]))
+
+;; Env Variable Value -> Value
+(define (ext r x i)
+  (cons (list x i) r))
+

knock-plus/interp.rkt

@@ -4,6 +4,7 @@
 (provide interp-match-pat)
 (require "ast.rkt")
 (require "interp-prim.rkt")
+(require "env.rkt")
 
 ;; type Value =
 ;; | Integer
@@ -167,15 +168,3 @@
      (cons (list x y)
            (zip xs ys))]))
 
-;; Env Id -> Value
-(define (lookup r x)
-  (match r
-    [(cons (list y val) r)
-     (if (symbol=? x y)
-         val
-         (lookup r x))]))
-
-;; Env Id Value -> Env
-(define (ext r x v)
-  (cons (list x v) r))
-