RecognizerSharedState Class

Namespace: Stimulsoft.Data.Expressions.Antlr.Runtime

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.

Constructors

Constructor Description
constructor()  

constructor()

Methods

Method Returns Description
recognizerSharedState static RecognizerSharedState  

Method Details

recognizerSharedState static

recognizerSharedState(state: RecognizerSharedState): RecognizerSharedState

Parameters

Returns RecognizerSharedState

Fields

Field Type Description
_fsp number  
backtracking number If 0, no backtracking is going on. Safe to exec actions etc… If >0 then it’s the level of backtracking.
channel number The channel number for the current token
errorRecovery boolean 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.
failed boolean In lieu of a return value, this indicates that a rule or token has failed to match. Reset to false upon valid token match.
following BitSet[]  
lastErrorIndex number 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.
ruleMemo Array<Dictionary<number, number» An array[size num rules] of dictionaries 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).
syntaxErrors number Did the recognizer encounter a syntax error? Track how many.
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.
token IToken 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.
tokenStartCharIndex number 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.
tokenStartCharPositionInLine number The character position of first character within the line
tokenStartLine number The line on which the first character of the token resides
type number The token type for the current token