Packageorg.antlr.runtime
Classpublic class RecognizerSharedState

The set of fields needed by an abstract recognizer to recognize input and recover from errors etc... As a separate state object, it can be shared among multiple grammars; e.g., when one grammar imports another. These fields are publically visible but the actual state pointer per parser is protected.


Public Properties
 PropertyDefined by
  backtracking : int = 0
If 0, no backtracking is going on.
RecognizerSharedState
  channel : int
The channel number for the current token
RecognizerSharedState
  errorRecovery : Boolean = false
This is true when we see an error and before having successfully matched a token.
RecognizerSharedState
  failed : Boolean = false
In lieu of a return value, this indicates that a rule or token has failed to match.
RecognizerSharedState
  following : Array
Track the set of token types that can follow any rule invocation.
RecognizerSharedState
  _fsp : int = -1
RecognizerSharedState
  lastErrorIndex : int = -1
The index into the input stream where the last error occurred.
RecognizerSharedState
  ruleMemo : Array
An Array[size num rules] of Arrays that tracks the stop token index for each rule.
RecognizerSharedState
  syntaxErrors : int = 0
Did the recognizer encounter a syntax error? Track how many.
RecognizerSharedState
  text : String
You can set the text for the current token to override what is in the input char buffer.
RecognizerSharedState
  token : Token
The goal of all lexer rules/methods is to create a token object.
RecognizerSharedState
  tokenStartCharIndex : int = -1
What character index in the stream did the current token start at? Needed, for example, to get the text for current token.
RecognizerSharedState
  tokenStartCharPositionInLine : int
The character position of first character within the line
RecognizerSharedState
  tokenStartLine : int
The line on which the first character of the token resides
RecognizerSharedState
  type : int
The token type for the current token
RecognizerSharedState
Property detail
backtrackingproperty
public var backtracking:int = 0

If 0, no backtracking is going on. Safe to exec actions etc... If >0 then it's the level of backtracking.

channelproperty 
public var channel:int

The channel number for the current token

errorRecoveryproperty 
public var errorRecovery:Boolean = false

This is true when we see an error and before having successfully matched a token. Prevents generation of more than one error message per error.

failedproperty 
public var failed:Boolean = false

In lieu of a return value, this indicates that a rule or token has failed to match. Reset to false upon valid token match.

followingproperty 
public var following:Array

Track the set of token types that can follow any rule invocation. Stack grows upwards. When it hits the max, it grows 2x in size and keeps going.

_fspproperty 
public var _fsp:int = -1
lastErrorIndexproperty 
public var lastErrorIndex:int = -1

The index into the input stream where the last error occurred. This is used to prevent infinite loops where an error is found but no token is consumed during recovery...another error is found, ad naseum. This is a failsafe mechanism to guarantee that at least one token/tree node is consumed for two errors.

ruleMemoproperty 
public var ruleMemo:Array

An Array[size num rules] of Arrays that tracks the stop token index for each rule. ruleMemo[ruleIndex] is the memoization table for ruleIndex. For key ruleStartIndex, you get back the stop token for associated rule or MEMO_RULE_FAILED. This is only used if rule memoization is on (which it is by default).

syntaxErrorsproperty 
public var syntaxErrors:int = 0

Did the recognizer encounter a syntax error? Track how many.

textproperty 
public var text:String

You can set the text for the current token to override what is in the input char buffer. Use setText() or can set this instance var.

tokenproperty 
public var token:Token

The goal of all lexer rules/methods is to create a token object. This is an instance variable as multiple rules may collaborate to create a single token. nextToken will return this object after matching lexer rule(s). If you subclass to allow multiple token emissions, then set this to the last token to be matched or something nonnull so that the auto token emit mechanism will not emit another token.

tokenStartCharIndexproperty 
public var tokenStartCharIndex:int = -1

What character index in the stream did the current token start at? Needed, for example, to get the text for current token. Set at the start of nextToken.

tokenStartCharPositionInLineproperty 
public var tokenStartCharPositionInLine:int

The character position of first character within the line

tokenStartLineproperty 
public var tokenStartLine:int

The line on which the first character of the token resides

typeproperty 
public var type:int

The token type for the current token