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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>
* How to execute code for node t when a visitor visits node t. Execute
* pre() before visiting children and execute post() after visiting children.
* </summary>
*/
public interface ITreeVisitorAction
{
/** <summary>
* Execute an action before visiting children of t. Return t or
* a rewritten t. It is up to the visitor to decide what to do
* with the return value. Children of returned value will be
* visited if using TreeVisitor.visit().
* </summary>
*/
object Pre( object t );
/** <summary>
* Execute an action after visiting children of t. Return t or
* a rewritten t. It is up to the visitor to decide what to do
* with the return value.
* </summary>
*/
object Post( object t );
}
public class TreeVisitorAction
: ITreeVisitorAction
{
private readonly Func<object, object> _preAction;
private readonly Func<object, object> _postAction;
public TreeVisitorAction( Func<object, object> preAction, Func<object, object> postAction )
{
_preAction = preAction;
_postAction = postAction;
}
public object Pre( object t )
{
if ( _preAction != null )
return _preAction( t );
return t;
}
public object Post( object t )
{
if ( _postAction != null )
return _postAction( t );
return t;
}
}
}
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