/Users/parrt/antlr/code/antlr/main/runtime/CSharp/Sources/Antlr3.Runtime/Antlr.Runtime.Tree/TreeParser.cs

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/*
[The "BSD licence"]
Copyright (c) 2007-2008 Johannes Luber
Copyright (c) 2005-2007 Kunle Odutola
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.
4. Unless explicitly state otherwise, any contribution intentionally 
   submitted for inclusion in this work to the copyright owner or licensor
   shall be under the terms and conditions of this license, without any 
   additional terms or conditions.

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
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(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 System;
        using Antlr.Runtime;
        
        public class TreeParser : BaseRecognizer
        {
                public const int DOWN = Token.DOWN;
                public const int UP   = Token.UP;

                public TreeParser(ITreeNodeStream input)
                        : base() // highlight that we go to super to set state object
                {
                        TreeNodeStream = input;
                }

                public TreeParser(ITreeNodeStream input, RecognizerSharedState state)
                        : base(state) // share the state object with another parser
                {
                        TreeNodeStream = input;
                }

                virtual public ITreeNodeStream TreeNodeStream
                {
                        get { return input; }
                        set { this.input = value; }
                }

                override public string SourceName {
                        get { return input.SourceName; }
                }

                protected override object GetCurrentInputSymbol(IIntStream input) {
                        return ((ITreeNodeStream)input).LT(1);
                }

                protected override object GetMissingSymbol(IIntStream input,
                                                                                  RecognitionException e,
                                                                                  int expectedTokenType,
                                                                                  BitSet follow) {
                        string tokenText = "<missing " + TokenNames[expectedTokenType] + ">";
                        return new CommonTree(new CommonToken(expectedTokenType, tokenText));
                }       

                override public void Reset() 
                {
                        base.Reset(); // reset all recognizer state variables
                        if ( input != null ) 
                        {
                                input.Seek(0); // rewind the input
                        }
                }

                override public void MatchAny(IIntStream ignore /* ignore stream param, it's a copy of this.input */) 
                {
                        state.errorRecovery = false;
                        state.failed = false;
                        object look = input.LT(1);
                        if ( input.TreeAdaptor.GetChildCount(look) == 0 ) 
                        {
                                input.Consume(); // not subtree, consume 1 node and return
                                return;
                        }
                        // current node is a subtree, skip to corresponding UP.
                        // must count nesting level to get right UP
                        int level = 0;
                        int tokenType = input.TreeAdaptor.GetNodeType(look);
                        while ( (tokenType != Token.EOF) && !( (tokenType == UP) && (level == 0) ) ) 
                        {
                                input.Consume();
                                look = input.LT(1);
                                tokenType = input.TreeAdaptor.GetNodeType(look);
                                if ( tokenType == DOWN ) 
                                {
                                        level++;
                                }
                                else if ( tokenType == UP ) 
                                {
                                        level--;
                                }
                        }
                        input.Consume(); // consume UP
                }

                override public IIntStream Input
                {
                        get { return input; } 
                }

                protected internal ITreeNodeStream input;

                protected internal override void Mismatch(IIntStream input, int ttype, BitSet follow) {
                        throw new MismatchedTreeNodeException(ttype, (ITreeNodeStream)input);
                }

                override public string GetErrorHeader(RecognitionException e)
                {
                        return GrammarFileName + ": node from "
                                + (e.approximateLineInfo ? "after " : "")
                                + "line " + e.Line + ":" + e.CharPositionInLine;
                }

                override public string GetErrorMessage(RecognitionException e, string[] tokenNames) 
                {
                        if ( this is TreeParser ) 
                        {
                                ITreeAdaptor adaptor = ((ITreeNodeStream)e.Input).TreeAdaptor;
                                e.Token = adaptor.GetToken(e.Node);
                                if ( e.Token == null ) 
                                { // could be an UP/DOWN node
                                        e.Token = new CommonToken(adaptor.GetNodeType(e.Node), adaptor.GetNodeText(e.Node));
                                }
                        }
                        return base.GetErrorMessage(e, tokenNames);
                }

                public virtual void TraceIn(string ruleName, int ruleIndex)  
                {
                        base.TraceIn(ruleName, ruleIndex, input.LT(1));
                }

                public virtual void TraceOut(string ruleName, int ruleIndex)  
                {
                        base.TraceOut(ruleName, ruleIndex, input.LT(1));
                }

        }
}

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