source: trunk/j/src/org/armedbear/lisp/with-hash-table-iterator.lisp @ 9266

Last change on this file since 9266 was 3640, checked in by piso, 18 years ago

Initial checkin.

File size: 1.4 KB
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1;;; with-hash-table-iterator.lisp
2;;;
3;;; Copyright (C) 2003 Peter Graves
4;;; $Id: with-hash-table-iterator.lisp,v 1.1 2003-09-09 23:21:04 piso Exp $
5;;;
6;;; This program is free software; you can redistribute it and/or
7;;; modify it under the terms of the GNU General Public License
8;;; as published by the Free Software Foundation; either version 2
9;;; of the License, or (at your option) any later version.
10;;;
11;;; This program is distributed in the hope that it will be useful,
12;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
13;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14;;; GNU General Public License for more details.
15;;;
16;;; You should have received a copy of the GNU General Public License
17;;; along with this program; if not, write to the Free Software
18;;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
19
20(in-package "SYSTEM")
21
22(defun hash-table-iterator-function (hash-table)
23  (let ((entries (hash-table-entries hash-table)))
24    #'(lambda () (let ((entry (car entries)))
25                   (setq entries (cdr entries))
26                   (if entry
27                       (values t (car entry) (cdr entry))
28                       nil)))))
29
30(defmacro with-hash-table-iterator ((name hash-table) &body body)
31  (let ((iter (gensym)))
32    `(let ((,iter (hash-table-iterator-function ,hash-table)))
33       (macrolet ((,name () '(funcall ,iter)))
34                 ,@body))))
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