diff options
| author | Rose Hogenson <rhogenson@posteo.net> | 2022-01-09 11:36:20 -0800 |
|---|---|---|
| committer | Rose Hogenson <rhogenson@posteo.net> | 2022-01-09 11:36:20 -0800 |
| commit | 6064e82e88b9a1d652b68bd1ea64f229aa76dd65 (patch) | |
| tree | 36569f9363739630c94e3215c7a14e4e42f72260 /match.csc | |
| parent | Add a library for pattern matching. (diff) | |
| download | chromatopelma-6064e82e88b9a1d652b68bd1ea64f229aa76dd65.tar.zst | |
Add wildcard to pattern syntax.
Diffstat (limited to 'match.csc')
| -rw-r--r-- | match.csc | 20 |
1 files changed, 15 insertions, 5 deletions
@@ -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 ...))) |