/*
* [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 ConditionalAttribute = System.Diagnostics.ConditionalAttribute;
using Regex = System.Text.RegularExpressions.Regex;
using RegexOptions = System.Text.RegularExpressions.RegexOptions;
/** <summary>
* A parser for a stream of tree nodes. "tree grammars" result in a subclass
* of this. All the error reporting and recovery is shared with Parser via
* the BaseRecognizer superclass.
* </summary>
*/
public class TreeParser : BaseRecognizer
{
public const int DOWN = TokenTypes.Down;
public const int UP = TokenTypes.Up;
// precompiled regex used by inContext
static string dotdot = ".*[^.]\\.\\.[^.].*";
static string doubleEtc = ".*\\.\\.\\.\\s+\\.\\.\\..*";
static Regex dotdotPattern = new Regex( dotdot, RegexOptions.Compiled );
static Regex doubleEtcPattern = new Regex( doubleEtc, RegexOptions.Compiled );
protected ITreeNodeStream input;
public TreeParser( ITreeNodeStream input )
: base() // highlight that we go to super to set state object
{
SetTreeNodeStream( input );
}
public TreeParser( ITreeNodeStream input, RecognizerSharedState state )
: base( state ) // share the state object with another parser
{
SetTreeNodeStream( input );
}
public override void Reset()
{
base.Reset(); // reset all recognizer state variables
if ( input != null )
{
input.Seek( 0 ); // rewind the input
}
}
/** <summary>Set the input stream</summary> */
public virtual void SetTreeNodeStream( ITreeNodeStream input )
{
this.input = input;
}
public virtual ITreeNodeStream GetTreeNodeStream()
{
return input;
}
public override 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] + ">";
ITreeAdaptor adaptor = ((ITreeNodeStream)e.Input).TreeAdaptor;
return adaptor.Create(new CommonToken(expectedTokenType, tokenText));
}
/** <summary>
* Match '.' in tree parser has special meaning. Skip node or
* entire tree if node has children. If children, scan until
* corresponding UP node.
* </summary>
*/
public override void MatchAny( IIntStream ignore )
{
state.errorRecovery = false;
state.failed = false;
// always consume the current node
input.Consume();
// if the next node is DOWN, then the current node is a subtree:
// skip to corresponding UP. must count nesting level to get right UP
int look = input.LA( 1 );
if ( look == DOWN )
{
input.Consume();
int level = 1;
while ( level > 0 )
{
switch ( input.LA( 1 ) )
{
case DOWN:
level++;
break;
case UP:
level--;
break;
case TokenTypes.EndOfFile:
return;
default:
break;
}
input.Consume();
}
}
}
/** <summary>
* We have DOWN/UP nodes in the stream that have no line info; override.
* plus we want to alter the exception type. Don't try to recover
* from tree parser errors inline...
* </summary>
*/
protected override object RecoverFromMismatchedToken( IIntStream input, int ttype, BitSet follow )
{
throw new MismatchedTreeNodeException( ttype, (ITreeNodeStream)input );
}
/** <summary>
* Prefix error message with the grammar name because message is
* always intended for the programmer because the parser built
* the input tree not the user.
* </summary>
*/
public override string GetErrorHeader( RecognitionException e )
{
return GrammarFileName + ": node from " +
( e.ApproximateLineInfo ? "after " : "" ) + "line " + e.Line + ":" + e.CharPositionInLine;
}
/** <summary>
* Tree parsers parse nodes they usually have a token object as
* payload. Set the exception token and do the default behavior.
* </summary>
*/
public override 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.GetType( e.Node ),
adaptor.GetText( e.Node ) );
}
}
return base.GetErrorMessage( e, tokenNames );
}
[Conditional("ANTLR_TRACE")]
public virtual void TraceIn( string ruleName, int ruleIndex )
{
base.TraceIn( ruleName, ruleIndex, input.LT( 1 ) );
}
[Conditional("ANTLR_TRACE")]
public virtual void TraceOut( string ruleName, int ruleIndex )
{
base.TraceOut( ruleName, ruleIndex, input.LT( 1 ) );
}
}
}