| /* |
| * [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; |
| |
| using Console = System.Console; |
| |
| public class TreeRewriter : TreeParser |
| { |
| protected bool showTransformations; |
| |
| protected ITokenStream originalTokenStream; |
| protected ITreeAdaptor originalAdaptor; |
| |
| Func<IAstRuleReturnScope> topdown_func; |
| Func<IAstRuleReturnScope> bottomup_func; |
| |
| public TreeRewriter( ITreeNodeStream input ) |
| : this( input, new RecognizerSharedState() ) |
| { |
| } |
| public TreeRewriter( ITreeNodeStream input, RecognizerSharedState state ) |
| : base( input, state ) |
| { |
| originalAdaptor = input.TreeAdaptor; |
| originalTokenStream = input.TokenStream; |
| topdown_func = () => Topdown(); |
| bottomup_func = () => Bottomup(); |
| } |
| |
| public virtual object ApplyOnce( object t, Func<IAstRuleReturnScope> whichRule ) |
| { |
| if ( t == null ) |
| return null; |
| |
| try |
| { |
| // share TreeParser object but not parsing-related state |
| state = new RecognizerSharedState(); |
| input = new CommonTreeNodeStream( originalAdaptor, t ); |
| ( (CommonTreeNodeStream)input ).TokenStream = originalTokenStream; |
| BacktrackingLevel = 1; |
| IAstRuleReturnScope r = whichRule(); |
| BacktrackingLevel = 0; |
| if ( Failed ) |
| return t; |
| |
| if (showTransformations && r != null && !t.Equals(r.Tree) && r.Tree != null) |
| ReportTransformation(t, r.Tree); |
| |
| if ( r != null && r.Tree != null ) |
| return r.Tree; |
| else |
| return t; |
| } |
| catch ( RecognitionException ) |
| { |
| } |
| |
| return t; |
| } |
| |
| public virtual object ApplyRepeatedly( object t, Func<IAstRuleReturnScope> whichRule ) |
| { |
| bool treeChanged = true; |
| while ( treeChanged ) |
| { |
| object u = ApplyOnce( t, whichRule ); |
| treeChanged = !t.Equals( u ); |
| t = u; |
| } |
| return t; |
| } |
| |
| public virtual object Downup( object t ) |
| { |
| return Downup( t, false ); |
| } |
| |
| public virtual object Downup( object t, bool showTransformations ) |
| { |
| this.showTransformations = showTransformations; |
| TreeVisitor v = new TreeVisitor( new CommonTreeAdaptor() ); |
| t = v.Visit( t, ( o ) => ApplyOnce( o, topdown_func ), ( o ) => ApplyRepeatedly( o, bottomup_func ) ); |
| return t; |
| } |
| |
| // methods the downup strategy uses to do the up and down rules. |
| // to override, just define tree grammar rule topdown and turn on |
| // filter=true. |
| public virtual IAstRuleReturnScope Topdown() |
| { |
| return null; |
| } |
| |
| public virtual IAstRuleReturnScope Bottomup() |
| { |
| return null; |
| } |
| |
| /** Override this if you need transformation tracing to go somewhere |
| * other than stdout or if you're not using ITree-derived trees. |
| */ |
| protected virtual void ReportTransformation(object oldTree, object newTree) |
| { |
| ITree old = oldTree as ITree; |
| ITree @new = newTree as ITree; |
| string oldMessage = old != null ? old.ToStringTree() : "??"; |
| string newMessage = @new != null ? @new.ToStringTree() : "??"; |
| Console.WriteLine("{0} -> {1}", oldMessage, newMessage); |
| } |
| } |
| } |