diff options
| -rw-r--r-- | match-test.csc | 12 | ||||
| -rw-r--r-- | match.csc | 20 |
2 files changed, 25 insertions, 7 deletions
diff --git a/match-test.csc b/match-test.csc index 3fed862..2728e44 100644 --- a/match-test.csc +++ b/match-test.csc @@ -18,7 +18,7 @@ (1 1) (2 2) (3 3) - (else 4)) + (_ 4)) 3) (test-case "match-list" @@ -27,12 +27,20 @@ ((1 2) 1) ((1 2 3) 2) ((1 2 3 4) 3) - (else 4)) + (_ 4)) 2) (test-case "binding" (match '(1 2 3) ((1 (! x) 3) x)) + 2) + (test-case + "ignore" + (match '(1 2 3) + ((_ _ _ _) 0) + ((2 _ _) 1) + ((1 _ _) 2) + (_ 3)) 2)))) (for-each (lambda (tc) @@ -5,16 +5,22 @@ (define-syntax matches? - (syntax-rules (!) + (syntax-rules (! _) ((matches? x '()) (null? x)) + ((matches? x _) #t) ((matches? x (! bind)) #t) + ((matches? x (_)) + (= 1 (length x))) ((matches? x ((! bind))) (= 1 (length x))) ((matches? x (lit)) (and (= 1 (length x)) (eqv? lit (car x)))) + ((matches? x (_ pattern1 pattern2 ...)) + (and (pair? x) + (matches? (cdr x) (pattern1 pattern2 ...)))) ((matches? x ((! bind) pattern1 pattern2 ...)) (and (pair? x) (matches? (cdr x) (pattern1 pattern2 ...)))) @@ -27,17 +33,23 @@ (define-syntax bind-pattern - (syntax-rules (!) + (syntax-rules (! _) ((bind-pattern x '() result1 result2 ...) (begin result1 result2 ...)) + ((bind-pattern x _ result1 result2 ...) + (begin result1 result2 ...)) ((bind-pattern x (! bind) result1 result2 ...) (let ((bind x)) result1 result2 ...)) + ((bind-pattern x (_) result1 result2 ...) + (begin result1 result2 ...)) ((bind-pattern x ((! bind)) result1 result2 ...) (let ((bind (car x))) result1 result2 ...)) ((bind-pattern x (lit) result1 result2 ...) (begin result1 result2 ...)) + ((bind-pattern x (_ pattern1 pattern2 ...) result1 result2 ...) + (bind-pattern (cdr x) (pattern1 pattern2 ...) result1 result2 ...)) ((bind-pattern x ((! bind) pattern1 pattern2 ...) result1 result2 ...) (let ((bind (car x))) (bind-pattern (cdr x) (pattern1 pattern2 ...) result1 result2 ...))) @@ -48,9 +60,7 @@ (define-syntax match - (syntax-rules (else) - ((match x (else result1 result2 ...)) - (begin result1 result2 ...)) + (syntax-rules () ((match x (pattern result1 result2 ...)) (if (matches? x pattern) (bind-pattern x pattern result1 result2 ...))) |