X-Git-Url: https://git.jsancho.org/?a=blobdiff_plain;ds=sidebyside;f=src%2Futils.scm;fp=src%2Futils.scm;h=5f56f0528703c5ad3d92da0e538d475019e48060;hb=f3d35ed115ff03f513c93a05325885e44da10891;hp=0000000000000000000000000000000000000000;hpb=253656b7188f5d1f3684a640530f248d29995eef;p=gacela.git

diff --git a/src/utils.scm b/src/utils.scm
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+;;; Gacela, a GNU Guile extension for fast games development
+;;; 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
+;;; the Free Software Foundation, either version 3 of the License, or
+;;; (at your option) any later version.
+;;;
+;;; This program is distributed in the hope that it will be useful,
+;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+(define-module (gacela utils)
+  #:export (make-producer))
+
+(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))))