1 package org.antlr.runtime { 2 3 /** The set of fields needed by an abstract recognizer to recognize input 4 * and recover from errors etc... As a separate state object, it can be 5 * shared among multiple grammars; e.g., when one grammar imports another. 6 * 7 * These fields are publically visible but the actual state pointer per 8 * parser is protected. 9 */ 10 public class RecognizerSharedState { 11 /** Track the set of token types that can follow any rule invocation. 12 * Stack grows upwards. When it hits the max, it grows 2x in size 13 * and keeps going. 14 */ 15 public var following:Array = new Array(); 16 public var _fsp:int = -1; 17 18 /** This is true when we see an error and before having successfully 19 * matched a token. Prevents generation of more than one error message 20 * per error. 21 */ 22 public var errorRecovery:Boolean = false; 23 24 /** The index into the input stream where the last error occurred. 25 * This is used to prevent infinite loops where an error is found 26 * but no token is consumed during recovery...another error is found, 27 * ad naseum. This is a failsafe mechanism to guarantee that at least 28 * one token/tree node is consumed for two errors. 29 */ 30 public var lastErrorIndex:int = -1; 31 32 /** In lieu of a return value, this indicates that a rule or token 33 * has failed to match. Reset to false upon valid token match. 34 */ 35 public var failed:Boolean = false; 36 37 /** Did the recognizer encounter a syntax error? Track how many. */ 38 public var syntaxErrors:int = 0; 39 40 /** If 0, no backtracking is going on. Safe to exec actions etc... 41 * If >0 then it's the level of backtracking. 42 */ 43 public var backtracking:int = 0; 44 45 /** An Array[size num rules] of Arrays that tracks 46 * the stop token index for each rule. ruleMemo[ruleIndex] is 47 * the memoization table for ruleIndex. For key ruleStartIndex, you 48 * get back the stop token for associated rule or MEMO_RULE_FAILED. 49 * 50 * This is only used if rule memoization is on (which it is by default). 51 */ 52 public var ruleMemo:Array; 53 54 55 // LEXER FIELDS (must be in same state object to avoid casting 56 // constantly in generated code and Lexer object) :( 57 58 59 /** The goal of all lexer rules/methods is to create a token object. 60 * This is an instance variable as multiple rules may collaborate to 61 * create a single token. nextToken will return this object after 62 * matching lexer rule(s). If you subclass to allow multiple token 63 * emissions, then set this to the last token to be matched or 64 * something nonnull so that the auto token emit mechanism will not 65 * emit another token. 66 */ 67 public var token:Token; 68 69 /** What character index in the stream did the current token start at? 70 * Needed, for example, to get the text for current token. Set at 71 * the start of nextToken. 72 */ 73 public var tokenStartCharIndex:int = -1; 74 75 /** The line on which the first character of the token resides */ 76 public var tokenStartLine:int; 77 78 /** The character position of first character within the line */ 79 public var tokenStartCharPositionInLine:int; 80 81 /** The channel number for the current token */ 82 public var channel:int; 83 84 /** The token type for the current token */ 85 public var type:int; 86 87 /** You can set the text for the current token to override what is in 88 * the input char buffer. Use setText() or can set this instance var. 89 */ 90 public var text:String; 91 } 92 93 }
