;;;; $Id: elib-node.el,v 0.8 1995/12/11 00:11:19 ceder Exp $ ;;;; Nodes used in binary trees and doubly linked lists. ;; Copyright (C) 1991-1995 Free Software Foundation ;; Author: Per Cederqvist ;; Inge Wallin ;; Maintainer: elib-maintainers@lysator.liu.se ;; Created: 20 May 1991 ;; Keywords: extensions, lisp ;;;; This file is part of the GNU Emacs lisp library, Elib. ;;;; ;;;; GNU Elib 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. ;;;; ;;;; GNU Elib 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 GNU Elib; see the file COPYING. If not, write to ;;;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330, ;;;; Boston, MA 02111-1307, USA ;;;; ;;;; Author: Inge Wallin ;;;; ;;; Commentary: ;;; A node is implemented as an array with three elements, using ;;; (elt node 0) as the left pointer ;;; (elt node 1) as the right pointer ;;; (elt node 2) as the data ;;; ;;; Some types of trees, e.g. AVL trees, need bigger nodes, but ;;; as long as the first three parts are the left pointer, the ;;; right pointer and the data field, these macros can be used. ;;; ;;; Code: (provide 'elib-node) (defmacro elib-node-create (left right data) ;; Create a tree node from LEFT, RIGHT and DATA. (` (vector (, left) (, right) (, data)))) (defmacro elib-node-left (node) ;; Return the left pointer of NODE. (` (aref (, node) 0))) (defmacro elib-node-right (node) ;; Return the right pointer of NODE. (` (aref (, node) 1))) (defmacro elib-node-data (node) ;; Return the data of NODE. (` (aref (, node) 2))) (defmacro elib-node-set-left (node newleft) ;; Set the left pointer of NODE to NEWLEFT. (` (aset (, node) 0 (, newleft)))) (defmacro elib-node-set-right (node newright) ;; Set the right pointer of NODE to NEWRIGHT. (` (aset (, node) 1 (, newright)))) (defmacro elib-node-set-data (node newdata) ;; Set the data of NODE to NEWDATA. (` (aset (, node) 2 (, newdata)))) (defmacro elib-node-branch (node branch) ;; Get value of a branch of a node. ;; ;; NODE is the node, and BRANCH is the branch. ;; 0 for left pointer, 1 for right pointer and 2 for the data." (` (aref (, node) (, branch)))) (defmacro elib-node-set-branch (node branch newval) ;; Set value of a branch of a node. ;; ;; NODE is the node, and BRANCH is the branch. ;; 0 for left pointer, 1 for the right pointer and 2 for the data. ;; NEWVAL is new value of the branch." (` (aset (, node) (, branch) (, newval)))) ;;; elib-node.el ends here.