Add utils module.

2 files changed, 34 insertions, 0 deletions

diff --git a/Makefile.am b/Makefile.am
index b29464b..7838b0b 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -40,6 +40,7 @@ godir=$(libdir)/guile/$(GUILE_EFFECTIVE_VERSION)/ccache
 
 SOURCES = 					\
   chickadee/config.scm				\
+  chickadee/utils.scm				\
   chickadee/input/controller.scm		\
   chickadee/math.scm				\
   chickadee/math/vector.scm			\
diff --git a/chickadee/utils.scm b/chickadee/utils.scm
new file mode 100644
index 0000000..4f989ac
--- /dev/null
+++ b/chickadee/utils.scm
@@ -0,0 +1,33 @@
+;;; Chickadee Game Toolkit
+;;; Copyright (C) 2014 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2016 David Thompson <davet@gnu.org>
+;;;
+;;; Chickadee 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.
+;;;
+;;; Chickadee 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 (chickadee utils)
+  #:export (memoize))
+
+;; Written by Ludovic Courtès.  Taken from GNU Guix.
+(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)))))))