| /* |
| * [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 ) ); |
| } |
| } |
| } |