1/*
2 [The "BSD licence"]
3 Copyright (c) 2005-2006 Terence Parr
4 All rights reserved.
5
6 Redistribution and use in source and binary forms, with or without
7 modification, are permitted provided that the following conditions
8 are met:
9 1. Redistributions of source code must retain the above copyright
10    notice, this list of conditions and the following disclaimer.
11 2. Redistributions in binary form must reproduce the above copyright
12    notice, this list of conditions and the following disclaimer in the
13    documentation and/or other materials provided with the distribution.
14 3. The name of the author may not be used to endorse or promote products
15    derived from this software without specific prior written permission.
16
17 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27*/
28package org.antlr.runtime {
29
30	/** A stream of tokens accessing tokens from a TokenSource */
31	public interface TokenStream extends IntStream {
32	    /** Get Token at current input pointer + i ahead where i=1 is next Token.
33		 *  i<0 indicates tokens in the past.  So -1 is previous token and -2 is
34		 *  two tokens ago. LT(0) is undefined.  For i>=n, return Token.EOFToken.
35		 *  Return null for LT(0) and any index that results in an absolute address
36		 *  that is negative.
37		 */
38	    function LT(k:int):Token;
39
40		/** Get a token at an absolute index i; 0..n-1.  This is really only
41		 *  needed for profiling and debugging and token stream rewriting.
42		 *  If you don't want to buffer up tokens, then this method makes no
43		 *  sense for you.  Naturally you can't use the rewrite stream feature.
44		 *  I believe DebugTokenStream can easily be altered to not use
45		 *  this method, removing the dependency.
46		 */
47		function getToken(i:int):Token;
48
49		/** Where is this stream pulling tokens from?  This is not the name, but
50		 *  the object that provides Token objects.
51		 */
52		function get tokenSource():TokenSource;
53
54		/** Return the text of all tokens from start to stop, inclusive.
55		 *  If the stream does not buffer all the tokens then it can just
56		 *  return "" or null;  Users should not access $ruleLabel.text in
57		 *  an action of course in that case.
58		 */
59		function toStringWithRange(start:int, stop:int):String;
60
61		/** Because the user is not required to use a token with an index stored
62		 *  in it, we must provide a means for two token objects themselves to
63		 *  indicate the start/end location.  Most often this will just delegate
64		 *  to the other toString(int,int).  This is also parallel with
65		 *  the TreeNodeStream.toString(Object,Object).
66		 */
67		function toStringWithTokenRange(start:Token, stop:Token):String;
68	}
69
70}