Handle pattern matching entire expressions

diff --git a/ast.scm b/ast.scm
index 109ce91a49ff95f7857550c0119f958b90caeefd..d2328cc6449d014eacb085fdc0b734f620c1ceb2 100644 (file)
--- a/ast.scm
+++ b/ast.scm
@@ -82,6 +82,9 @@
     ['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)]))
 

diff --git a/tests.scm b/tests.scm
index 49fc2c4bc861b13de41f454a7aa2b6e6b103d8d9..7185032945aab633c43d3fcf0b0f1c24d55d0eb9 100644 (file)
--- a/tests.scm
+++ b/tests.scm
@@ -169,6 +169,19 @@
       y)))
  'Int)
 
+                                       ; case statements
+(test-types
+ (typecheck '((data A (foo B))
+             (data B (bar Int))
+             (case (foo (bar 32))
+               [(foo x) x])))
+ 'B)
+
+(test-types
+ (typecheck '((case 42
+               [23 (= 1 2)]
+               [x (= x 1)])))
+ 'Bool)
 
                                        ; type annotations
 
@@ -282,8 +295,8 @@
 (test-prog '((data Foo [a] [b] [c])
             (let ([x b])
               (case x
-                [a 1]
-                [b 2]
-                [c 3])))
+                [a b]
+                [b a]
+                [c x])))
           2)
 

diff --git a/typecheck.scm b/typecheck.scm
index ebfd816ad62a9538839c808187d55cbeaad593db..064f65f696459d08b38f3e20e00f8ff180b23bc7 100644 (file)
--- a/typecheck.scm
+++ b/typecheck.scm
@@ -193,16 +193,19 @@
   (define (check-match switch-type x)
     (let ([pattern (car x)]
          [expr (cadr x)])
-      (if (eqv? (ast-type pattern) 'app)
+      (case (ast-type pattern)
+       ['app
                                        ; a pattern match with bindings
          (let ([sum (assoc (car pattern) (cdr (assoc switch-type dls)))])
            (unless sum (error #f "can't pattern match ~a with ~a" switch-type pattern))
            (let* ([names (cdr pattern)]
                   [types (cdr sum)]
                   [new-env (fold-left env-insert env names types)])
-             (check dls new-env expr)))
+             (check dls new-env expr)))]
+                                       ; pattern match with binding and no constructor
+       ['var (check dls (env-insert env pattern switch-type) expr)]
                                        ; a pattern match without bindings
-         (check dls env expr))))
+       [else (check dls env expr)])))
   
   (let* ([switch-type-res (check dls env (case-switch x))]
         [switch-type (cadr switch-type-res)]
@@ -216,9 +219,9 @@
 
         [resolved-type (substitute case-expr-equality-cs (car case-expr-types))]
 
-        [annotated `((case (,(case-expr x) : ,switch-type)
-                       ,(map (lambda (c e et)
-                               `(,c (,e : ,et)))
+        [annotated `((case (,(case-switch x) : ,switch-type)
+                       ,@(map (lambda (c e et)
+                                `(,c ((,e : ,et))))
                               (map car (case-cases x))
                               (map cadr (case-cases x))
                               case-expr-types)) : ,resolved-type)]
@@ -345,11 +348,15 @@
        `((let ,(map (lambda (o n) (list (car o) (denormalize (cadr o) (cadr n))))
                     (let-bindings orig)
                     (let-bindings (ann-expr normed)))
-           ,@(map (lambda (o n) (denormalize o n))
+           ,@(map denormalize
                   (let-body orig)
                   (let-body (ann-expr normed)))) : ,(ann-type normed))]
     ['if `((if ,@(map denormalize (cdr orig) (cdr (ann-expr normed))))
-          : (ann-type normed))]
+          : ,(ann-type normed))]
+    ['case `((case ,(denormalize (case-switch orig) (case-switch (ann-expr normed)))
+              ,@(map (lambda (o n) (cons (car o) (denormalize (cadr o) (cadr n))))
+                     (case-cases orig) (case-cases (ann-expr normed))))
+            : ,(ann-type normed))]
     [else normed]))
 
 (define ann-expr car)
@@ -359,7 +366,9 @@
 (define (annotate-types prog)
   (denormalize
    (program-body prog)
-   (caddr (check (init-adts-env prog) (normalize (program-body prog))))))
+   (caddr (check (program-data-layouts prog)
+                (init-adts-env prog)
+                (normalize (program-body prog))))))
 
   
                                        ; returns a list of constraints