Add in map from underlying scheme for Exercise 4.14

This doesn't work, as described in the question, so back out of this branch.

dd-mceval.rkt

@@ -607,6 +607,7 @@
         (list '/ /)
         (list '< <)
         (list '> >)
+        (list 'map map)
 ;;      more primitives
         ))
 
@@ -720,6 +721,20 @@
   ;; (map fib '(1 2 3 4 5 6 7 8 9 10)) ->  (1 1 2 3 5 8 13 21 34 55)
   )
 
-
+;; Exercise 4.14
+
+;; Using map from the underlying interpreter doesn't work, because the
+;; interpreter and interpreted language have different representations
+;; of procedures.  If we use the underlying map and pass it a
+;; procedure from the interpreted language, it just sees a list
+;; '(procedure ...), which is just a list of symbols in the underlying
+;; lisp.
+
+;; map definition
+(define (my-map f x)
+  (if (null? x)
+      '()
+      (cons (f (car x))
+            (my-map f (cdr x)))))