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//
// ANTLRTreeVisitor.m
// ANTLR
//
// Created by Alan Condit on 6/18/10.
// [The "BSD licence"]
// Copyright (c) 2010 Alan Condit
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// 3. The name of the author may not be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
// IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
// OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
// IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
// NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
// THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#import "ANTLRTreeVisitor.h"
#import "ANTLRCommonTreeAdaptor.h"
@implementation ANTLRTreeVisitor
+ (ANTLRTreeVisitor *)newANTLRTreeVisitor:(id<ANTLRTreeAdaptor>)anAdaptor
{
return [[ANTLRTreeVisitor alloc] initWithAdaptor:anAdaptor];
}
+ (ANTLRTreeVisitor *)newANTLRTreeVisitor
{
return [[ANTLRTreeVisitor alloc] init];
}
- (id)init
{
if ((self = [super init]) != nil) {
adaptor = [[ANTLRCommonTreeAdaptor newTreeAdaptor] retain];
}
return self;
}
- (id)initWithAdaptor:(id<ANTLRTreeAdaptor>)anAdaptor
{
if ((self = [super init]) != nil) {
adaptor = [anAdaptor retain];
}
return self;
}
- (void) dealloc
{
#ifdef DEBUG_DEALLOC
NSLog( @"called dealloc in ANTLRTreeVisitor" );
#endif
if ( adaptor ) [adaptor release];
[super dealloc];
}
/** Visit every node in tree t and trigger an action for each node
* before/after having visited all of its children.
* Execute both actions even if t has no children.
* If a child visit yields a new child, it can update its
* parent's child list or just return the new child. The
* child update code works even if the child visit alters its parent
* and returns the new tree.
*
* Return result of applying post action to this node.
*/
- (ANTLRTreeVisitor *)visit:(ANTLRCommonTree *)t Action:(ANTLRTreeVisitorAction *)action
{
// System.out.println("visit "+((Tree)t).toStringTree());
BOOL isNil = [adaptor isNil:t];
if ( action != nil && !isNil ) {
t = [action pre:(ANTLRTreeVisitorAction *)t]; // if rewritten, walk children of new t
}
for (int i=0; i < [adaptor getChildCount:t]; i++) {
ANTLRCommonTree *child = [adaptor getChild:t At:i];
ANTLRCommonTree *visitResult = [self visit:child Action:action];
ANTLRCommonTree *childAfterVisit = [adaptor getChild:t At:i];
if ( visitResult != childAfterVisit ) { // result & child differ?
[adaptor setChild:t At:i Child:visitResult];
}
}
if ( action != nil && !isNil ) t = [action post:(ANTLRTreeVisitorAction *)t];
return t;
}
@synthesize adaptor;
@end
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