Merge branch 'release/0.6'

[gacela.git] / src / utils.scm

diff --git a/src/utils.scm b/src/utils.scm
index 4a27f88706c30e146dd7397c842699784b930601..5f56f0528703c5ad3d92da0e538d475019e48060 100644 (file)
--- a/src/utils.scm
+++ b/src/utils.scm
@@ -1,5 +1,5 @@
 ;;; Gacela, a GNU Guile extension for fast games development
-;;; Copyright (C) 2009 by Javier Sancho Fernandez <jsf at jsancho dot org>
+;;; Copyright (C) 2016 by Javier Sancho Fernandez <jsf at jsancho dot org>
 ;;;
 ;;; This program is free software: you can redistribute it and/or modify
 ;;; it under the terms of the GNU General Public License as published by
@@ -16,18 +16,18 @@
 
 
 (define-module (gacela utils)
-  #:use-module (ice-9 session)
-  #:export (use-cache-with))
+  #:export (make-producer))
 
-
-;;; Cache for procedures
-(define (use-cache-with proc)
-  (let ((cache (make-weak-value-hash-table)))
-    (lambda (. param)
-      (let* ((key param)
-            (res (hash-ref cache key)))
-       (cond (res res)
-             (else
-              (set! res (apply proc param))
-              (hash-set! cache key res)
-              res))))))
+(define (make-producer body)
+  (define resume #f)
+  (lambda (real-send)
+    (define send-to real-send)
+    (define (send value-to-send)
+      (set! send-to
+       (call/cc
+        (lambda (k)
+          (set! resume k)
+          (send-to value-to-send)))))
+    (if resume
+       (resume real-send)
+       (body send))))