141 lines
4.8 KiB
C#
141 lines
4.8 KiB
C#
/*
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* [The "BSD licence"]
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* Copyright (c) 2005-2008 Terence Parr
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* All rights reserved.
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*
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* Conversion to C#:
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* Copyright (c) 2008-2009 Sam Harwell, Pixel Mine, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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namespace Antlr.Runtime.Debug
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{
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using System.Collections.Generic;
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using ParseTree = Antlr.Runtime.Tree.ParseTree;
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/** <summary>
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* This parser listener tracks rule entry/exit and token matches
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* to build a simple parse tree using ParseTree nodes.
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* </summary>
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*/
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public class ParseTreeBuilder : BlankDebugEventListener
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{
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public const string EPSILON_PAYLOAD = "<epsilon>";
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Stack<ParseTree> callStack = new Stack<ParseTree>();
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List<IToken> hiddenTokens = new List<IToken>();
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int backtracking = 0;
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public ParseTreeBuilder( string grammarName )
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{
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ParseTree root = Create( "<grammar " + grammarName + ">" );
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callStack.Push( root );
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}
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public virtual ParseTree Tree
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{
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get
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{
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ParseTree[] stack = callStack.ToArray();
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return stack[stack.Length - 1];
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}
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}
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/** <summary>
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* What kind of node to create. You might want to override
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* so I factored out creation here.
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* </summary>
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*/
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public virtual ParseTree Create( object payload )
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{
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return new ParseTree( payload );
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}
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public virtual ParseTree EpsilonNode()
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{
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return Create( EPSILON_PAYLOAD );
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}
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/** <summary>Backtracking or cyclic DFA, don't want to add nodes to tree</summary> */
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public override void EnterDecision( int d, bool couldBacktrack )
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{
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backtracking++;
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}
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public override void ExitDecision( int i )
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{
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backtracking--;
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}
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public override void EnterRule( string filename, string ruleName )
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{
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if ( backtracking > 0 )
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return;
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ParseTree parentRuleNode = callStack.Peek();
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ParseTree ruleNode = Create( ruleName );
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parentRuleNode.AddChild( ruleNode );
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callStack.Push( ruleNode );
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}
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public override void ExitRule( string filename, string ruleName )
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{
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if ( backtracking > 0 )
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return;
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ParseTree ruleNode = callStack.Peek();
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if ( ruleNode.ChildCount == 0 )
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{
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ruleNode.AddChild( EpsilonNode() );
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}
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callStack.Pop();
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}
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public override void ConsumeToken( IToken token )
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{
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if ( backtracking > 0 )
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return;
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ParseTree ruleNode = callStack.Peek();
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ParseTree elementNode = Create( token );
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elementNode.hiddenTokens = this.hiddenTokens;
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this.hiddenTokens = new List<IToken>();
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ruleNode.AddChild( elementNode );
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}
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public override void ConsumeHiddenToken( IToken token )
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{
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if ( backtracking > 0 )
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return;
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hiddenTokens.Add( token );
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}
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public override void RecognitionException( RecognitionException e )
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{
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if ( backtracking > 0 )
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return;
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ParseTree ruleNode = callStack.Peek();
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ParseTree errorNode = Create( e );
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ruleNode.AddChild( errorNode );
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}
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}
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}
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