X-Git-Url: http://git.lukelau.me/?p=scheme.git;a=blobdiff_plain;f=ast.scm;h=d2328cc6449d014eacb085fdc0b734f620c1ceb2;hp=52e06bcb24d3b4783eb301c8fb657ec7f7e06071;hb=a457cd3bb5ce9366db3ca0731a07abc50ecbc1f3;hpb=1b7e2b53e68a39265fd7424910998d2607cc3815

diff --git a/ast.scm b/ast.scm
index 52e06bc..d2328cc 100644
--- a/ast.scm
+++ b/ast.scm
@@ -17,6 +17,7 @@
       ('if 'if)
       ('let 'let)
       ('lambda 'lambda)
+      ('case 'case)
       ('closure 'closure) ; only available in codegen
       ('static-string 'static-string) ; only available in codegen
       ('stack 'stack) ; only available in codegen (tag that value is passed via stack)
@@ -35,6 +36,10 @@
     ('app (map f x))
     ('lambda `(lambda ,(lambda-args x) ,(f (lambda-body x))))
     ('if `(if ,@(map f (cdr x))))
+    ('case `(case ,(f (case-switch x))
+	      ,@(map (lambda (x)
+		       (list (car x) (f (cadr x))))
+		     (case-cases x))))
     ('stack `(stack ,(cadr x) ,(f (caddr x))))
     (else x)))
 
@@ -50,6 +55,9 @@
 		     (inner (lambda-body x)))]
     ['if (append (f x)
 		 (flat-map inner (cdr x)))]
+    ['case (append (f x)
+		   (inner (case-switch x))
+		   (flat-map inner (map cadr (case-cases x))))]
     ['stack (append (f x)
 		    (inner (caddr x)))]
     [else (f x)]))
@@ -74,12 +82,54 @@
     ['lambda (either (p x)
 		     (inner (lambda-body x)))]
     ['if (either (p x) (any inner (cdr x)))]
+    ['case (either (p x)
+		   (any inner (map cadr (case-cases x)))
+		   (inner (case-switch x)))]
     ['stack (either (p x) (inner (caddr x)))]
     [else (p x)]))
 
 (define let-bindings cadr)
 (define let-body cddr)
 
+(define case-switch cadr)
+(define case-cases cddr)
+
+;; (define (verify-cases data-layouts annotated-program)
+
+;;   (define allowed-match-ast-types    
+;;     '((Int . (int-literal var))
+;;       (Bool . (bool-literal var))
+;;       (String . (string-literal var))))
+
+;;   (define (check-pattern switch-type pat)
+
+;;     (define (impossible-match)
+;;       (error "Can't pattern match ~a with ~a" switch-type (ann-expr pat)))
+
+;;     (if (assoc switch-type data-layouts)
+;; 	(begin
+;; 	  (let ([sums (cdr (assoc switch-type data-layouts))])
+;; 	    (unless (eqv? (ast-type (ann-expr pat)) 'var) (impossible-match))
+;; 	    (unless (assoc (car (ann-expr pat)) sums) (impossible-match))
+;; 	    (unless 
+;; 	  )
+;;        (begin
+;; 	 (unless (assoc switch-type allowed-match-ast-types)
+;; 	   (error #f "Can't pattern match on ~a" switch-type))
+	 
+;; 	 (let ([allowed (cdr (assoc switch-type allowed-match-ast-types))])
+;; 	   (unless (assoc (ast-type (ann-expr pat)) allowed) (impossible-match)))))))
+
+  
+;;   (let ([expr (ann-expr annotated-program)])
+;;     (case (ast-type expr)
+;;       ['case
+;; 	  (let* ([switch-type (ann-type (case-switch expr))]
+;; 		 [allowed (cdr (assoc switch-type allowed-match-ast-types))])
+;; 	    (for-each 
+;; 	      []))]))))
+
+
 					; (let ([(foo a b) (foo 123 345)]) a)
 					;   |
 					;   v
@@ -87,7 +137,7 @@
                                         ;       [b (foo~1 (foo 123 345)]) a)
 (define (expand-pattern-matches program)
   (define (go x)
-    (define (pattern-match binding)
+    (define (let-pattern-match binding)
       (let ([binding-name (car binding)]
 	    [body (cadr binding)])
 	(if (eqv? (ast-type binding-name) 'var)
@@ -121,11 +171,12 @@
 			       binding)))
 	      
 	      (flat-map (lambda (y i)
-			  (pattern-match (list y `(,(destructor i) ,body))))
+			  (let-pattern-match (list y `(,(destructor i) ,body))))
 			products
 			(range 0 (length products)))))))
+
     (case (ast-type x)
-      ['let `(let ,(flat-map pattern-match (let-bindings x))
+      ['let `(let ,(flat-map let-pattern-match (let-bindings x))
 	       ,@(map go (let-body x)))]
       [else (ast-traverse go x)]))
   (program-map-exprs go program))