125 lines
4.6 KiB
C#
125 lines
4.6 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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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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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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ParseTree root = Create("<grammar " + grammarName + ">");
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callStack.Push(root);
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}
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public virtual ParseTree GetTree() {
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var enumerator = callStack.GetEnumerator();
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enumerator.MoveNext();
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return enumerator.Current;
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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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return new ParseTree(payload);
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}
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public virtual ParseTree EpsilonNode() {
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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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backtracking++;
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}
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public override void ExitDecision(int i) {
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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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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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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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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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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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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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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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