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      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 */
     28 package org.antlr.runtime {
     29     import org.antlr.runtime.tree.TreeAdaptor;
     30 
     31 	/** A parser for TokenStreams.  "parser grammars" result in a subclass
     32 	 *  of this.
     33 	 */
     34 	public class Parser extends BaseRecognizer {
     35 	    protected var input:TokenStream;
     36 
     37 		public function Parser(input:TokenStream, state:RecognizerSharedState = null) {
     38 			super(state);
     39 			tokenStream = input;
     40 	    }
     41 
     42 		public override function reset():void {
     43 			super.reset(); // reset all recognizer state variables
     44 			if ( input!=null ) {
     45 				input.seek(0); // rewind the input
     46 			}
     47 		}
     48 
     49 		protected override function getCurrentInputSymbol(input:IntStream):Object {
     50 			return TokenStream(input).LT(1);
     51 		}
     52 
     53 		protected override function getMissingSymbol(input:IntStream,
     54 										    e:RecognitionException,
     55 										    expectedTokenType:int,
     56 										    follow:BitSet):Object {
     57 		    var tokenText:String = null;
     58             if ( expectedTokenType==TokenConstants.EOF ) tokenText = "<missing EOF>";
     59             else tokenText = "<missing "+tokenNames[expectedTokenType]+">";
     60 			var t:CommonToken = new CommonToken(expectedTokenType, tokenText);
     61 			var current:Token = TokenStream(input).LT(1);
     62 			if ( current.type == TokenConstants.EOF ) {
     63 				current = TokenStream(input).LT(-1);
     64 			}
     65 			t.line = current.line;
     66 			t.charPositionInLine = current.charPositionInLine;
     67 			t.channel = DEFAULT_TOKEN_CHANNEL;
     68 			return t;
     69 		}
     70 
     71 		/** Set the token stream and reset the parser */
     72 		public function set tokenStream(input:TokenStream):void {
     73 			this.input = null;
     74 			reset();
     75 			this.input = input;
     76 		}
     77 
     78 	    public function get tokenStream():TokenStream {
     79 			return input;
     80 		}
     81 
     82 		public override function get sourceName():String {
     83 			return input.sourceName;
     84 		}
     85 
     86 		public function set treeAdaptor(adaptor:TreeAdaptor):void {
     87 		    // do nothing, implemented in generated code
     88 		}
     89 
     90 		public function get treeAdaptor():TreeAdaptor {
     91 		    // implementation provided in generated code
     92 		    return null;
     93 		}
     94 
     95 		public function traceIn(ruleName:String, ruleIndex:int):void  {
     96 			super.traceInSymbol(ruleName, ruleIndex, input.LT(1));
     97 		}
     98 
     99 		public function traceOut(ruleName:String, ruleIndex:int):void {
    100 			super.traceOutSymbol(ruleName, ruleIndex, input.LT(1));
    101 		}
    102 	}
    103 
    104 }