1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
|
;; memoize.jl -- create caching-enabled functions
;; Copyright (C) 2000 John Harper <john@dcs.warwick.ac.uk>
;; $Id: memoize.jl,v 1.5 2000/07/23 22:24:33 john Exp $
;; This file is part of librep.
;; librep 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 2, or (at your option)
;; any later version.
;; librep 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 librep; see the file COPYING. If not, write to
;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
(define-structure rep.util.memoize
(export memoize memoize-function)
(open rep
rep.data.tables)
(define-structure-alias memoize rep.util.memoize)
(define (memoize f)
"Create and return a caching version of the function F. F may not be
an autoload definition."
(unless (functionp f)
(error "can only memoize functions: %s" f))
(let ((cache (make-table equal-hash equal)))
(lambda args
(or (table-ref cache args)
(table-set cache args (apply f args))))))
;; backwards compatibility
(define memoize-function memoize))
|
