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
33namespace 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