| /* |
| * [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.Debug |
| { |
| using System.Collections.Generic; |
| using ParseTree = Antlr.Runtime.Tree.ParseTree; |
| |
| /** <summary> |
| * This parser listener tracks rule entry/exit and token matches |
| * to build a simple parse tree using ParseTree nodes. |
| * </summary> |
| */ |
| public class ParseTreeBuilder : BlankDebugEventListener |
| { |
| public const string EPSILON_PAYLOAD = "<epsilon>"; |
| |
| Stack<ParseTree> callStack = new Stack<ParseTree>(); |
| List<IToken> hiddenTokens = new List<IToken>(); |
| int backtracking = 0; |
| |
| public ParseTreeBuilder( string grammarName ) |
| { |
| ParseTree root = Create( "<grammar " + grammarName + ">" ); |
| callStack.Push( root ); |
| } |
| |
| public virtual ParseTree Tree |
| { |
| get |
| { |
| return callStack.Peek(); |
| } |
| } |
| |
| /** <summary> |
| * What kind of node to create. You might want to override |
| * so I factored out creation here. |
| * </summary> |
| */ |
| public virtual ParseTree Create( object payload ) |
| { |
| return new ParseTree( payload ); |
| } |
| |
| public virtual ParseTree EpsilonNode() |
| { |
| return Create( EPSILON_PAYLOAD ); |
| } |
| |
| /** <summary>Backtracking or cyclic DFA, don't want to add nodes to tree</summary> */ |
| public override void EnterDecision( int d, bool couldBacktrack ) |
| { |
| backtracking++; |
| } |
| public override void ExitDecision( int i ) |
| { |
| backtracking--; |
| } |
| |
| public override void EnterRule( string filename, string ruleName ) |
| { |
| if ( backtracking > 0 ) |
| return; |
| ParseTree parentRuleNode = callStack.Peek(); |
| ParseTree ruleNode = Create( ruleName ); |
| parentRuleNode.AddChild( ruleNode ); |
| callStack.Push( ruleNode ); |
| } |
| |
| public override void ExitRule( string filename, string ruleName ) |
| { |
| if ( backtracking > 0 ) |
| return; |
| ParseTree ruleNode = callStack.Peek(); |
| if ( ruleNode.ChildCount == 0 ) |
| { |
| ruleNode.AddChild( EpsilonNode() ); |
| } |
| callStack.Pop(); |
| } |
| |
| public override void ConsumeToken( IToken token ) |
| { |
| if ( backtracking > 0 ) |
| return; |
| ParseTree ruleNode = callStack.Peek(); |
| ParseTree elementNode = Create( token ); |
| elementNode.hiddenTokens = this.hiddenTokens; |
| this.hiddenTokens = new List<IToken>(); |
| ruleNode.AddChild( elementNode ); |
| } |
| |
| public override void ConsumeHiddenToken( IToken token ) |
| { |
| if ( backtracking > 0 ) |
| return; |
| hiddenTokens.Add( token ); |
| } |
| |
| public override void RecognitionException( RecognitionException e ) |
| { |
| if ( backtracking > 0 ) |
| return; |
| ParseTree ruleNode = callStack.Peek(); |
| ParseTree errorNode = Create( e ); |
| ruleNode.AddChild( errorNode ); |
| } |
| } |
| } |