X-Git-Url: http://git.lukelau.me/?a=blobdiff_plain;f=ast.scm;h=8a986173d675f43eb58cd0c5f7c6c7c679175d9f;hb=c4a5f8ab1efce20f0e1181ffe34639facb19594a;hp=6b546ac6f4214a2a9891e10da74ea8df7b5c1ed0;hpb=7be98b67cbad421a0b041d20e0f4620e70bd4cd6;p=scheme.git

diff --git a/ast.scm b/ast.scm
index 6b546ac..8a98617 100644
--- a/ast.scm
+++ b/ast.scm
@@ -75,19 +75,31 @@
     ['stack (either (p x) (inner (caddr x)))]
     [else (p x)]))
 
-(define (let-bindings e)
-  (define (pattern-match binding body)
-    (if (eqv? (ast-type binding) 'var)
-	(list (cons binding body))
-	(let* ([constructor (car binding)]
-	       [destructor (lambda (i) (dtor-name constructor i))])
-	  (flat-map (lambda (y i)
-		      (pattern-match y `((,(destructor i) ,@body))))
-		    (cdr binding)
-		    (range 0 (length (cdr binding)))))))
-  (flat-map (lambda (x) (pattern-match (car x) (cdr x))) (cadr e)))
+(define let-bindings cadr)
 (define let-body cddr)
 
+					; (let ([(foo a b) (foo 123 345)]) a)
+					;   |
+					;   v
+					; (let ([a (foo~0 (foo 123 345)]
+                                        ;       [b (foo~1 (foo 123 345)]) a)
+(define (expand-pattern-matches x)  
+  (define (pattern-match binding)
+    (let ([binding-name (car binding)]
+	  [body (cadr binding)])
+      (if (eqv? (ast-type binding-name) 'var)
+	  (list (list binding-name body))
+	  (let* ([sum-name (car binding-name)]
+		 [destructor (lambda (i) (dtor-name sum-name i))])
+	    (flat-map (lambda (y i)
+			(pattern-match (list y `(,(destructor i) ,body))))
+		      (cdr binding-name)
+		      (range 0 (length (cdr binding-name))))))))
+  (case (ast-type x)
+      ['let `(let ,(flat-map pattern-match (let-bindings x))
+	          ,@(map expand-pattern-matches (let-body x)))]
+      [else (ast-traverse expand-pattern-matches x)]))
+
 (define (lambda? x)
   (and (list? x) (eq? (car x) 'lambda)))
 
@@ -112,24 +124,32 @@
   (filter (lambda (x) (eqv? (statement-type x) 'defines))
 	  program))
 
+(define (program-map-exprs f program)
+  (map (lambda (x)
+	 (case (statement-type x)
+	   ['expr (f x)]
+	   [else x]))
+       program))
+
 (define (program-body program)
   ; hack to have multi-expression bodies
   `(let ()
      ,@(filter (lambda (x) (eqv? (statement-type x) 'expr))
 	       program)))
 
-
-
-					; gets both constructors and destructors
+					; a data tor is either a constructor or destructor for an ADT
+					; data-tors returns constructors and destructors for a data-layout
 					; (data A (foo Int Bool)
 					;         (bar Bool))
 					;        |
 					;        v
-					; (foo . (constructor . (abs Int (abs Bool A))))
-					; (foo~0 . (0 . (abs A Int)))
-					; (foo~1 . (1 . (abs A Bool)))
-					; (bar . (constructor . (abs Bool A)))
-					; (bar~0 . (0 . (abs A Bool)))
+					; (foo   . ((A foo constructor) . (abs Int (abs Bool A))))
+					; (foo~0 . ((A foo 0)           . (abs A Int)))
+					; (foo~1 . ((A foo 1)           . (abs A Bool)))
+					; (bar   . ((A bar constructor) . (abs Bool A)))
+					; (bar~0 . ((A bar 0)           . (abs A Bool)))
+					;  ------+-------------------------------------
+					;  tor   | info                 | type
 
 (define (data-tors data-layout)
   (define (constructor-type t products)
@@ -137,7 +157,7 @@
 
   (define (destructor ctor-name prod-type part-type index)
     (let ([name (dtor-name ctor-name index)])
-      (cons name (cons index `(abs ,prod-type ,part-type)))))
+      (cons name (cons (list prod-type ctor-name index) `(abs ,prod-type ,part-type)))))
   
   (let ([type-name (car data-layout)]
         [ctors (cdr data-layout)])
@@ -146,7 +166,7 @@
        (let* ([ctor-name (car ctor)]
 	      [products (cdr ctor)]
 	      
-	      [maker (cons ctor-name (cons 'constructor (constructor-type type-name products)))]
+	      [maker (cons ctor-name (cons (list type-name ctor-name 'constructor) (constructor-type type-name products)))]
 	      
 	      [dtors (map (lambda (t i) (destructor ctor-name type-name t i))
 			  products
@@ -156,7 +176,7 @@
      ctors)))
 
 					; creates a type environment for a given adt definition
-(define (data-tors-env data-layout)
+(define (data-tors-type-env data-layout)
   (map (lambda (x) (cons (car x) (cddr x))) (data-tors data-layout)))
 
 (define (dtor-name ctor-name index)