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      1 /*
      2  * [The "BSD licence"]
      3  * Copyright (c) 2005-2008 Terence Parr
      4  * All rights reserved.
      5  *
      6  * Conversion to C#:
      7  * Copyright (c) 2008-2009 Sam Harwell, Pixel Mine, Inc.
      8  * All rights reserved.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. The name of the author may not be used to endorse or promote products
     19  *    derived from this software without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     31  */
     32 
     33 namespace Antlr.Runtime
     34 {
     35 
     36     /** <summary>
     37      *  A source of tokens must provide a sequence of tokens via nextToken()
     38      *  and also must reveal it's source of characters; CommonToken's text is
     39      *  computed from a CharStream; it only store indices into the char stream.
     40      *  </summary>
     41      *
     42      *  <remarks>
     43      *  Errors from the lexer are never passed to the parser.  Either you want
     44      *  to keep going or you do not upon token recognition error.  If you do not
     45      *  want to continue lexing then you do not want to continue parsing.  Just
     46      *  throw an exception not under RecognitionException and Java will naturally
     47      *  toss you all the way out of the recognizers.  If you want to continue
     48      *  lexing then you should not throw an exception to the parser--it has already
     49      *  requested a token.  Keep lexing until you get a valid one.  Just report
     50      *  errors and keep going, looking for a valid token.
     51      *  </summary>
     52      */
     53     public interface ITokenSource
     54     {
     55         /** <summary>
     56          *  Return a Token object from your input stream (usually a CharStream).
     57          *  Do not fail/return upon lexing error; keep chewing on the characters
     58          *  until you get a good one; errors are not passed through to the parser.
     59          *  </summary>
     60          */
     61         IToken NextToken();
     62 
     63         /** <summary>
     64          *  Where are you getting tokens from? normally the implication will simply
     65          *  ask lexers input stream.
     66          *  </summary>
     67          */
     68         string SourceName
     69         {
     70             get;
     71         }
     72 
     73         string[] TokenNames
     74         {
     75             get;
     76         }
     77     }
     78 }
     79