1// 2// TreeVisitor.m 3// ANTLR 4// 5// Created by Alan Condit on 6/18/10. 6// [The "BSD licence"] 7// Copyright (c) 2010 Alan Condit 8// All rights reserved. 9// 10// Redistribution and use in source and binary forms, with or without 11// modification, are permitted provided that the following conditions 12// are met: 13// 1. Redistributions of source code must retain the above copyright 14// notice, this list of conditions and the following disclaimer. 15// 2. Redistributions in binary form must reproduce the above copyright 16// notice, this list of conditions and the following disclaimer in the 17// documentation and/or other materials provided with the distribution. 18// 3. The name of the author may not be used to endorse or promote products 19// derived from this software without specific prior written permission. 20// 21// THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22// IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23// OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24// IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26// NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30// THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 32#import "TreeVisitor.h" 33#import "CommonTreeAdaptor.h" 34 35@implementation TreeVisitor 36 37+ (TreeVisitor *)newTreeVisitor:(id<TreeAdaptor>)anAdaptor 38{ 39 return [[TreeVisitor alloc] initWithAdaptor:anAdaptor]; 40} 41 42+ (TreeVisitor *)newTreeVisitor 43{ 44 return [[TreeVisitor alloc] init]; 45} 46 47 48- (id)init 49{ 50 if ((self = [super init]) != nil) { 51 adaptor = [[CommonTreeAdaptor newTreeAdaptor] retain]; 52 } 53 return self; 54} 55 56- (id)initWithAdaptor:(id<TreeAdaptor>)anAdaptor 57{ 58 if ((self = [super init]) != nil) { 59 adaptor = [anAdaptor retain]; 60 } 61 return self; 62} 63 64- (void) dealloc 65{ 66#ifdef DEBUG_DEALLOC 67 NSLog( @"called dealloc in TreeVisitor" ); 68#endif 69 if ( adaptor ) [adaptor release]; 70 [super dealloc]; 71} 72 73/** Visit every node in tree t and trigger an action for each node 74 * before/after having visited all of its children. 75 * Execute both actions even if t has no children. 76 * If a child visit yields a new child, it can update its 77 * parent's child list or just return the new child. The 78 * child update code works even if the child visit alters its parent 79 * and returns the new tree. 80 * 81 * Return result of applying post action to this node. 82 */ 83- (id<BaseTree>)visit:(id<BaseTree>)t Action:(TreeVisitorAction *)action 84{ 85 // System.out.println("visit "+((Tree)t).toStringTree()); 86 BOOL isNil = [adaptor isNil:t]; 87 if ( action != nil && !isNil ) { 88 t = [action pre:(id<BaseTree>)t]; // if rewritten, walk children of new t 89 } 90 for (int i=0; i < [adaptor getChildCount:t]; i++) { 91 id<BaseTree> child = [adaptor getChild:t At:i]; 92 id<BaseTree> visitResult = [self visit:child Action:action]; 93 id<BaseTree> childAfterVisit = [adaptor getChild:t At:i]; 94 if ( visitResult != childAfterVisit ) { // result & child differ? 95 [adaptor setChild:t At:i Child:visitResult]; 96 } 97 } 98 if ( action != nil && !isNil ) t = [action post:(id<BaseTree>)t]; 99 return t; 100} 101 102@synthesize adaptor; 103@end 104