X-Git-Url: https://git.lukelau.me/?p=scheme.git;a=blobdiff_plain;f=ast.scm;h=b70317a70e6fd3a14aa9fab5c94be57991427f2e;hp=b3f21bd07d6d07ba2b64017cff0a365cbf77abd4;hb=8e106ca13666680051f91ab3f49ce2bd7e19ead7;hpb=006b94f5a24a794665788737fec8d54086284317

diff --git a/ast.scm b/ast.scm
index b3f21bd..b70317a 100644
--- a/ast.scm
+++ b/ast.scm
@@ -1,3 +1,5 @@
+(load "utils.scm")
+
 (define (ast-type x)
   (define (builtin? x)
     (case x
@@ -33,7 +35,7 @@
     ('app (map f x))
     ('lambda `(lambda ,(lambda-args x) ,(f (lambda-body x))))
     ('if `(if ,@(map f (cdr x))))
-    ('stack `(stack ,(cadr x) ,(map f (caddr x))))
+    ('stack `(stack ,(cadr x) ,(f (caddr x))))
     (else x)))
 
 (define (ast-collect f x)
@@ -99,10 +101,17 @@
 
 		   [type (data-tor-type data-layouts sum-name)]
 
-		   [sum (assoc sum-name (cdr (assoc type data-layouts)))]
+		   [sums (cdr (assoc type data-layouts))]
+		   [sum (assoc sum-name sums)]
 		   
 		   [expected-number (length (cdr sum))])
 
+					; assert that we only do a let pattern match on an ADT with exactly one sum
+	      (when (not (= 1 (length sums)))
+		(error #f (format "Cannot pattern match a ~a in a let since it has ~a possible constructors"
+				  type
+				  (length sums))))
+
 					; assert that there is the correct number of bindings
 	      (when (not (= (length products)
 			    expected-number))
@@ -322,26 +331,3 @@
 	   (strong-connect v)))
        (car graph)))
     result))
-
-
-					; utils
-
-(define (range s n)
-  (if (= 0 n) '()
-      (append (range s (- n 1))
-	      (list (+ s (- n 1))))))
-
-(define (flat-map f . xs) (fold-left append '() (apply map (cons f xs))))
-(define (repeat x n) (if (<= n 0) '()
-			 (cons x (repeat x (- n 1)))))
-
-
-(define-syntax push!
-  (syntax-rules ()
-    ((_ s x) (set! s (cons x s)))))
-
-(define-syntax pop!
-  (syntax-rules ()
-    ((_ s) (let ([x (car s)])
-	     (set! s (cdr s))
-	     x))))