Issue #489 - Guarantee order of eval begin exprs

Guarantee that sub-expressions of a begin are evaluated in order. The code was reversing the results of a map. However map is not necessarily guaranteed to evaluate its arguments in any given order because it could be optimized into another function such as `Cyc-map-loop-1`. Instead we just use the optimized function directly as a more general `map` is not required here and this function is guaranteed to process its argument list in a predicable order.

CHANGELOG.md

@@ -9,6 +9,10 @@ Features
 
 Bug Fixes
 
+- Prevent an error when evaluating a `begin` expression that contains both a macro definition and an application of that macro. For example:
+
+      begin (define-syntax foo (syntax-rules () ((foo) 123))) (foo))
+
 - Fix a regression where `c-compiler-options` was not recognized as a top level form by programs.
 - Enforce a maximum recursion depth when printing an object via `display` and `write`, and when comparing objects via `equal?`. This prevents segmentation faults when working with circular data structures.
 

scheme/eval.sld

@@ -636,14 +636,9 @@
 ;(display "/* ")
 ;(write (list exp))
 ;(display "*/ ")
-       (let ((fncs 
+       (let ((fncs (Cyc-map-loop-1 (lambda (expr) 
-               ;; Our map starts from the end, we reverse
+                                      (analyze expr a-env rename-env local-renamed))
-               ;; so everything is evaluated in order, then
+                                   (cdr exp))))
-               ;; reverse again so results are in order
-               (reverse
-                 (map (lambda (expr) 
-                        (analyze expr a-env rename-env local-renamed))
-                      (reverse (cdr exp))))))
          (lambda (env)
            (foldl (lambda (fnc _) (fnc env)) #f fncs))))
       ;; compiled macro