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| author | David Thompson <dthompson2@worcester.edu> | 2021-03-05 07:47:57 -0500 |
|---|---|---|
| committer | David Thompson <dthompson2@worcester.edu> | 2021-03-05 07:47:57 -0500 |
| commit | 48df59c37e5fb1a2f5061589bfba4e3c155e2f08 (patch) | |
| tree | 004e8bb17b499b353fb5ba6abd4d4d5679c1fd11 | |
| parent | 764155b7422301c497012989658fa6423bf1fd99 (diff) | |
utils: Add for-range macro.
| -rw-r--r-- | .dir-locals.el | 3 | ||||
| -rw-r--r-- | chickadee/utils.scm | 24 |
2 files changed, 25 insertions, 2 deletions
diff --git a/.dir-locals.el b/.dir-locals.el index f255f96..9eb5b8e 100644 --- a/.dir-locals.el +++ b/.dir-locals.el @@ -28,4 +28,5 @@ (eval . (put 'with-graphics-state! 'scheme-indent-function 1)) (eval . (put 'translate 'scheme-indent-function 1)) (eval . (put 'rotate 'scheme-indent-function 1)) - (eval . (put 'scale 'scheme-indent-function 1))))) + (eval . (put 'scale 'scheme-indent-function 1)) + (eval . (put 'for-range 'scheme-indent-function 1))))) diff --git a/chickadee/utils.scm b/chickadee/utils.scm index 4f989ac..e2a20c1 100644 --- a/chickadee/utils.scm +++ b/chickadee/utils.scm @@ -17,7 +17,8 @@ ;;; <http://www.gnu.org/licenses/>. (define-module (chickadee utils) - #:export (memoize)) + #:export (memoize + for-range)) ;; Written by Ludovic Courtès. Taken from GNU Guix. (define (memoize proc) @@ -31,3 +32,24 @@ list))) (hash-set! cache args results) (apply values results))))))) + +(define-syntax for-range + (syntax-rules () + ((_ ((var end start inc)) body ...) + (let* ((s start) ; evaluate start/end only once + (e end) + (reverse? (< e s)) + (start* (if reverse? e s)) + (end* (if reverse? s e))) + (let loop ((var start*)) + (when (< var end*) + body ... + (loop (+ var inc)))))) + ((_ ((var end start)) body ...) + (for-range ((var end start 1)) body ...)) + ((_ ((var end)) body ...) + (for-range ((var end 0 1)) body ...)) + ((_ ((var args ...) rest ...) body ...) + (for-range ((var args ...)) + (for-range (rest ...) + body ...))))) |