org.antlr.v4.runtime.atn

Class LexerATNSimulator.SimState

java.lang.Object

org.antlr.v4.runtime.atn.LexerATNSimulator.SimState

Enclosing class:

LexerATNSimulator

protected static class LexerATNSimulator.SimState
extends Object

When we hit an accept state in either the DFA or the ATN, we have to notify the character stream to start buffering characters via IntStream.mark() and record the current state. The current sim state includes the current index into the input, the current line, and current character position in that line. Note that the Lexer is tracking the starting line and characterization of the token. These variables track the "state" of the simulator when it hits an accept state.

We track these variables separately for the DFA and ATN simulation because the DFA simulation often has to fail over to the ATN simulation. If the ATN simulation fails, we need the DFA to fall back to its previously accepted state, if any. If the ATN succeeds, then the ATN does the accept and the DFA simulator that invoked it can simply return the predicted token type.

Field Summary

Fields

Modifier and Type	Field and Description
protected int	charPos
protected DFAState	dfaState
protected int	index
protected int	line

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	SimState()

Method Summary

Modifier and Type	Method and Description
protected void	reset()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

index

protected int index

line

protected int line

charPos

protected int charPos

dfaState

protected DFAState dfaState

Constructor Detail

SimState

protected SimState()

Method Detail

reset

protected void reset()