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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          */
NextToken()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