01: /*
02: * simple_list_remove_duplicates.java
03: *
04: * Copyright (C) 2004 Peter Graves
05: * $Id: simple_list_remove_duplicates.java,v 1.1 2004/03/13 17:49:00 piso Exp $
06: *
07: * This program is free software; you can redistribute it and/or
08: * modify it under the terms of the GNU General Public License
09: * as published by the Free Software Foundation; either version 2
10: * of the License, or (at your option) any later version.
11: *
12: * This program is distributed in the hope that it will be useful,
13: * but WITHOUT ANY WARRANTY; without even the implied warranty of
14: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15: * GNU General Public License for more details.
16: *
17: * You should have received a copy of the GNU General Public License
18: * along with this program; if not, write to the Free Software
19: * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
20: */
21:
22: package org.armedbear.lisp;
23:
24: // ### simple-list-remove-duplicates
25: public final class simple_list_remove_duplicates extends Primitive1 {
26: private simple_list_remove_duplicates() {
27: super ("simple-list-remove-duplicates", PACKAGE_SYS, false,
28: "list");
29: }
30:
31: public LispObject execute(LispObject list)
32: throws ConditionThrowable {
33: LispObject result = NIL;
34: while (list != NIL) {
35: LispObject item = list.car();
36: boolean duplicate = false;
37: LispObject tail = list.cdr();
38: while (tail != NIL) {
39: if (item.eql(tail.car())) {
40: duplicate = true;
41: break;
42: }
43: tail = tail.cdr();
44: }
45: if (!duplicate)
46: result = new Cons(item, result);
47: list = list.cdr();
48: }
49: return result.nreverse();
50: }
51:
52: private static final Primitive1 SIMPLE_LIST_REMOVE_DUPLICATES = new simple_list_remove_duplicates();
53: }
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