Add bindings to pattern matching in case statement typechecking

[scheme.git] / ast.scm

diff --git a/ast.scm b/ast.scm
index 86d522560a8012546e6a754499b1216052d8ce70..109ce91a49ff95f7857550c0119f958b90caeefd 100644 (file)
--- a/ast.scm
+++ b/ast.scm
@@ -36,7 +36,7 @@
     ('app (map f x))
     ('lambda `(lambda ,(lambda-args x) ,(f (lambda-body x))))
     ('if `(if ,@(map f (cdr x))))
-    ('case `(case ,(f (case-expr x))
+    ('case `(case ,(f (case-switch x))
              ,@(map (lambda (x)
                       (list (car x) (f (cadr x))))
                     (case-cases x))))
@@ -56,7 +56,7 @@
     ['if (append (f x)
                 (flat-map inner (cdr x)))]
     ['case (append (f x)
-                  (inner (case-expr x))
+                  (inner (case-switch x))
                   (flat-map inner (map cadr (case-cases x))))]
     ['stack (append (f x)
                    (inner (caddr x)))]
@@ -88,9 +88,45 @@
 (define let-bindings cadr)
 (define let-body cddr)
 
-(define case-expr cadr)
+(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
@@ -98,7 +134,7 @@
                                         ;       [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)
@@ -132,11 +168,12 @@
                               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))