diff options
Diffstat (limited to '2d/helpers.scm')
| -rw-r--r-- | 2d/helpers.scm | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/2d/helpers.scm b/2d/helpers.scm index 59633d6..4082377 100644 --- a/2d/helpers.scm +++ b/2d/helpers.scm @@ -1,5 +1,6 @@ ;;; guile-2d ;;; Copyright (C) 2013, 2014 David Thompson <dthompson2@worcester.edu> +;;; Copyright (C) 2014 Ludovic Courtès <ludo@gnu.org> ;;; ;;; This program is free software: you can redistribute it and/or ;;; modify it under the terms of the GNU General Public License as @@ -28,7 +29,8 @@ #:use-module (2d game) #:export (any-equal? logand? - define-guardian)) + define-guardian + memoize)) (define (any-equal? elem . args) "Return #t if ELEM equals any of the elements in the list ARGS." @@ -51,3 +53,16 @@ same thread that is running the game loop." (when obj (reaper obj) (reap (name)))))))) + +(define (memoize proc) + "Return a memoizing version of PROC." + (let ((cache (make-hash-table))) + (lambda args + (let ((results (hash-ref cache args))) + (if results + (apply values results) + (let ((results (call-with-values (lambda () + (apply proc args)) + list))) + (hash-set! cache args results) + (apply values results))))))) |