antlr-3.4/runtime/CSharp2/Sources/Antlr3.Runtime/Antlr.Runtime/ITokenSource.cs

/*
[The "BSD licence"]
Copyright (c) 2007-2008 Johannes Luber
Copyright (c) 2005-2007 Kunle Odutola
All rights reserved.

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   derived from this software without specific prior WRITTEN permission.
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   submitted for inclusion in this work to the copyright owner or licensor
   shall be under the terms and conditions of this license, without any 
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namespace Antlr.Runtime
{
	using System;
	
	/// <summary>
	/// A source of tokens must provide a sequence of tokens via NextToken()
	/// and also must reveal it's source of characters; CommonToken's text is
	/// computed from a CharStream; it only store indices into the char stream.
	/// 
	/// Errors from the lexer are never passed to the parser.  Either you want
	/// to keep going or you do not upon token recognition error.  If you do not
	/// want to continue lexing then you do not want to continue parsing.  Just
	/// throw an exception not under RecognitionException and Java will naturally
	/// toss you all the way out of the recognizers.  If you want to continue
	/// lexing then you should not throw an exception to the parser--it has already
	/// requested a token.  Keep lexing until you get a valid one.  Just report
	/// errors and keep going, looking for a valid token.
	/// </summary>
	public interface ITokenSource
	{
		/// <summary>
		/// Returns a Token object from the input stream (usually a CharStream).
		/// Does not fail/return upon lexing error; just keeps chewing on the 
		/// characters until it gets a good one; errors are not passed through 
		/// to the parser.
		/// </summary>
		IToken NextToken();

		/// <summary>
		/// Where are you getting tokens from? normally the implication will simply
		/// ask lexers input stream.
		/// </summary>
		string SourceName {
			get;
		}
	}
}