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/*
* [The "BSD licence"]
* Copyright (c) 2005-2008 Terence Parr
* All rights reserved.
*
* Conversion to C#:
* Copyright (c) 2008-2009 Sam Harwell, Pixel Mine, Inc.
* 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.
*/
namespace Antlr.Runtime.Tree
{
using Antlr.Runtime.Misc;
/** <summary>Do a depth first walk of a tree, applying pre() and post() actions as we go.</summary> */
public class TreeVisitor
{
protected ITreeAdaptor adaptor;
public TreeVisitor( ITreeAdaptor adaptor )
{
this.adaptor = adaptor;
}
public TreeVisitor()
: this( new CommonTreeAdaptor() )
{
}
/** <summary>
* Visit every node in tree t and trigger an action for each node
* before/after having visited all of its children. Bottom up walk.
* Execute both actions even if t has no children. Ignore return
* results from transforming children since they will have altered
* the child list of this node (their parent). Return result of
* applying post action to this node.
* </summary>
*/
public object Visit( object t, ITreeVisitorAction action )
{
// System.out.println("visit "+((Tree)t).toStringTree());
bool isNil = adaptor.IsNil( t );
if ( action != null && !isNil )
{
t = action.Pre( t ); // if rewritten, walk children of new t
}
for ( int i = 0; i < adaptor.GetChildCount(t); i++ )
{
object child = adaptor.GetChild( t, i );
Visit( child, action );
}
if ( action != null && !isNil )
t = action.Post( t );
return t;
}
public object Visit( object t, Func<object, object> preAction, Func<object, object> postAction )
{
return Visit( t, new TreeVisitorAction( preAction, postAction ) );
}
}
}