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	import org.antlr.runtime.tree.Tree;
30	import org.antlr.runtime.tree.TreeNodeStream;
31	import org.antlr.runtime.tree.TreeAdaptor;
32	import org.antlr.runtime.tree.CommonTree;
33	/** The root of the ANTLR exception hierarchy.
34	 *
35	 *  To avoid English-only error messages and to generally make things
36	 *  as flexible as possible, these exceptions are not created with strings,
37	 *  but rather the information necessary to generate an error.  Then
38	 *  the various reporting methods in Parser and Lexer can be overridden
39	 *  to generate a localized error message.  For example, MismatchedToken
40	 *  exceptions are built with the expected token type.
41	 *  So, don't expect getMessage() to return anything.
42	 *
43	 *  Note that as of Java 1.4, you can access the stack trace, which means
44	 *  that you can compute the complete trace of rules from the start symbol.
45	 *  This gives you considerable context information with which to generate
46	 *  useful error messages.
47	 *
48	 *  ANTLR generates code that throws exceptions upon recognition error and
49	 *  also generates code to catch these exceptions in each rule.  If you
50	 *  want to quit upon first error, you can turn off the automatic error
51	 *  handling mechanism using rulecatch action, but you still need to
52	 *  override methods mismatch and recoverFromMismatchSet.
53	 *
54	 *  In general, the recognition exceptions can track where in a grammar a
55	 *  problem occurred and/or what was the expected input.  While the parser
56	 *  knows its state (such as current input symbol and line info) that
57	 *  state can change before the exception is reported so current token index
58	 *  is computed and stored at exception time.  From this info, you can
59	 *  perhaps print an entire line of input not just a single token, for example.
60	 *  Better to just say the recognizer had a problem and then let the parser
61	 *  figure out a fancy report.
62	 */
63	public class RecognitionException extends Error {
64		/** What input stream did the error occur in? */
65		public var input:IntStream;
66
67		/** What is index of token/char were we looking at when the error occurred? */
68		public var index:int;
69
70		/** The current Token when an error occurred.  Since not all streams
71		 *  can retrieve the ith Token, we have to track the Token object.
72		 *  For parsers.  Even when it's a tree parser, token might be set.
73		 */
74		public var token:Token;
75
76		/** If this is a tree parser exception, node is set to the node with
77		 *  the problem.
78		 */
79		public var node:Object;
80
81		/** The current char when an error occurred. For lexers. */
82		public var c:int;
83
84		/** Track the line at which the error occurred in case this is
85		 *  generated from a lexer.  We need to track this since the
86		 *  unexpected char doesn't carry the line info.
87		 */
88		public var line:int;
89
90		public var charPositionInLine:int;
91
92		/** If you are parsing a tree node stream, you will encounter som
93		 *  imaginary nodes w/o line/col info.  We now search backwards looking
94		 *  for most recent token with line/col info, but notify getErrorHeader()
95		 *  that info is approximate.
96		 */
97		public var approximateLineInfo:Boolean;
98
99		public function RecognitionException(input:IntStream = null) {
100			if (input == null) {
101				return;
102			}
103			this.input = input;
104			this.index = input.index;
105			if ( input is TokenStream ) {
106				this.token = TokenStream(input).LT(1);
107				this.line = token.line;
108				this.charPositionInLine = token.charPositionInLine;
109			}
110			if ( input is TreeNodeStream ) {
111				extractInformationFromTreeNodeStream(input);
112			}
113			else if ( input is CharStream ) {
114				this.c = input.LA(1);
115				this.line = CharStream(input).line;
116				this.charPositionInLine = CharStream(input).charPositionInLine;
117			}
118			else {
119				this.c = input.LA(1);
120			}
121		}
122
123		protected function extractInformationFromTreeNodeStream(input:IntStream):void {
124			var nodes:TreeNodeStream = TreeNodeStream(input);
125			this.node = nodes.LT(1);
126			var adaptor:TreeAdaptor = nodes.treeAdaptor;
127			var payload:Token = adaptor.getToken(node);
128			if ( payload!=null ) {
129				this.token = payload;
130				if ( payload.line<= 0 ) {
131					// imaginary node; no line/pos info; scan backwards
132					var i:int = -1;
133					var priorNode:Object = nodes.LT(i);
134					while ( priorNode!=null ) {
135						var priorPayload:Token = adaptor.getToken(priorNode);
136						if ( priorPayload!=null && priorPayload.line > 0 ) {
137							// we found the most recent real line / pos info
138							this.line = priorPayload.line;
139							this.charPositionInLine = priorPayload.charPositionInLine;
140							this.approximateLineInfo = true;
141							break;
142						}
143						--i;
144						priorNode = nodes.LT(i);
145					}
146				}
147				else { // node created from real token
148					this.line = payload.line;
149					this.charPositionInLine = payload.charPositionInLine;
150				}
151			}
152			else if ( this.node is Tree) {
153				this.line = this.node.line;
154				this.charPositionInLine = this.node.charPositionInLine;
155				if ( this.node is CommonTree) {
156					this.token = this.node.token;
157				}
158			}
159			else {
160				var type:int = adaptor.getType(this.node);
161				var text:String = adaptor.getText(this.node);
162				this.token = new CommonToken(type, text);
163			}
164		}
165
166		/** Return the token type or char of the unexpected input element */
167		public function get unexpectedType():int {
168			if ( input is TokenStream ) {
169				return token.type;
170			}
171			else if ( input is TreeNodeStream ) {
172				var nodes:TreeNodeStream = TreeNodeStream(input);
173				var adaptor:TreeAdaptor = nodes.treeAdaptor;
174				return adaptor.getType(node);
175			}
176			else {
177				return c;
178			}
179
180		}
181	}
182
183}