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comparison lisp/pcl-cvs/elib-node.el @ 0:376386a54a3c r19-14

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date Mon, 13 Aug 2007 08:45:50 +0200
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1 ;;;; $Id: elib-node.el,v 1.1.1.1 1996/12/18 03:32:27 steve Exp $
2 ;;;; Nodes used in binary trees and doubly linked lists.
3
4 ;; Copyright (C) 1991-1995 Free Software Foundation
5
6 ;; Author: Per Cederqvist <ceder@lysator.liu.se>
7 ;; Inge Wallin <inge@lysator.liu.se>
8 ;; Maintainer: elib-maintainers@lysator.liu.se
9 ;; Created: 20 May 1991
10 ;; Keywords: extensions, lisp
11
12 ;;;; This file is part of the GNU Emacs lisp library, Elib.
13 ;;;;
14 ;;;; GNU Elib is free software; you can redistribute it and/or modify
15 ;;;; it under the terms of the GNU General Public License as published by
16 ;;;; the Free Software Foundation; either version 2, or (at your option)
17 ;;;; any later version.
18 ;;;;
19 ;;;; GNU Elib is distributed in the hope that it will be useful,
20 ;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
21 ;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 ;;;; GNU General Public License for more details.
23 ;;;;
24 ;;;; You should have received a copy of the GNU General Public License
25 ;;;; along with GNU Elib; see the file COPYING. If not, write to
26 ;;;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
27 ;;;; Boston, MA 02111-1307, USA
28 ;;;;
29 ;;;; Author: Inge Wallin
30 ;;;;
31
32 ;;; Commentary:
33
34 ;;; A node is implemented as an array with three elements, using
35 ;;; (elt node 0) as the left pointer
36 ;;; (elt node 1) as the right pointer
37 ;;; (elt node 2) as the data
38 ;;;
39 ;;; Some types of trees, e.g. AVL trees, need bigger nodes, but
40 ;;; as long as the first three parts are the left pointer, the
41 ;;; right pointer and the data field, these macros can be used.
42 ;;;
43
44 ;;; Code:
45
46 (provide 'elib-node)
47
48
49 (defmacro elib-node-create (left right data)
50
51 ;; Create a tree node from LEFT, RIGHT and DATA.
52 (` (vector (, left) (, right) (, data))))
53
54
55 (defmacro elib-node-left (node)
56
57 ;; Return the left pointer of NODE.
58 (` (aref (, node) 0)))
59
60
61 (defmacro elib-node-right (node)
62
63 ;; Return the right pointer of NODE.
64 (` (aref (, node) 1)))
65
66
67 (defmacro elib-node-data (node)
68
69 ;; Return the data of NODE.
70 (` (aref (, node) 2)))
71
72
73 (defmacro elib-node-set-left (node newleft)
74
75 ;; Set the left pointer of NODE to NEWLEFT.
76 (` (aset (, node) 0 (, newleft))))
77
78
79 (defmacro elib-node-set-right (node newright)
80
81 ;; Set the right pointer of NODE to NEWRIGHT.
82 (` (aset (, node) 1 (, newright))))
83
84
85 (defmacro elib-node-set-data (node newdata)
86 ;; Set the data of NODE to NEWDATA.
87 (` (aset (, node) 2 (, newdata))))
88
89
90
91 (defmacro elib-node-branch (node branch)
92
93 ;; Get value of a branch of a node.
94 ;;
95 ;; NODE is the node, and BRANCH is the branch.
96 ;; 0 for left pointer, 1 for right pointer and 2 for the data."
97 (` (aref (, node) (, branch))))
98
99
100 (defmacro elib-node-set-branch (node branch newval)
101
102 ;; Set value of a branch of a node.
103 ;;
104 ;; NODE is the node, and BRANCH is the branch.
105 ;; 0 for left pointer, 1 for the right pointer and 2 for the data.
106 ;; NEWVAL is new value of the branch."
107 (` (aset (, node) (, branch) (, newval))))
108
109 ;;; elib-node.el ends here.