1 // 2 // ANTLRTreeVisitor.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 "ANTLRTreeVisitor.h" 33 #import "ANTLRCommonTreeAdaptor.h" 34 35 @implementation ANTLRTreeVisitor 36 37 + (ANTLRTreeVisitor *)newANTLRTreeVisitor:(id<ANTLRTreeAdaptor>)anAdaptor 38 { 39 return [[ANTLRTreeVisitor alloc] initWithAdaptor:anAdaptor]; 40 } 41 42 + (ANTLRTreeVisitor *)newANTLRTreeVisitor 43 { 44 return [[ANTLRTreeVisitor alloc] init]; 45 } 46 47 48 - (id)init 49 { 50 if ((self = [super init]) != nil) { 51 adaptor = [[ANTLRCommonTreeAdaptor newTreeAdaptor] retain]; 52 } 53 return self; 54 } 55 56 - (id)initWithAdaptor:(id<ANTLRTreeAdaptor>)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 ANTLRTreeVisitor" ); 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 - (ANTLRTreeVisitor *)visit:(ANTLRCommonTree *)t Action:(ANTLRTreeVisitorAction *)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:(ANTLRTreeVisitorAction *)t]; // if rewritten, walk children of new t 89 } 90 for (int i=0; i < [adaptor getChildCount:t]; i++) { 91 ANTLRCommonTree *child = [adaptor getChild:t At:i]; 92 ANTLRCommonTree *visitResult = [self visit:child Action:action]; 93 ANTLRCommonTree *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:(ANTLRTreeVisitorAction *)t]; 99 return t; 100 } 101 102 @synthesize adaptor; 103 @end 104
