Class: SimState

Inherits:
Object show all
Defined in:
lib/antlr4/atn/LexerATNSimulator.rb

Overview

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 {@link 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.

<p>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.</p>

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ SimState

Returns a new instance of SimState.



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# File 'lib/antlr4/atn/LexerATNSimulator.rb', line 19

def initialize
    self.reset()
end

Instance Attribute Details

#column ⇒ Object

Returns the value of attribute column.



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# File 'lib/antlr4/atn/LexerATNSimulator.rb', line 18

def column
  @column
end

#dfaState ⇒ Object

Returns the value of attribute dfaState.



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# File 'lib/antlr4/atn/LexerATNSimulator.rb', line 18

def dfaState
  @dfaState
end

#index ⇒ Object

Returns the value of attribute index.



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# File 'lib/antlr4/atn/LexerATNSimulator.rb', line 18

def index
  @index
end

#line ⇒ Object

Returns the value of attribute line.



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# File 'lib/antlr4/atn/LexerATNSimulator.rb', line 18

def line
  @line
end

Instance Method Details

#reset ⇒ Object 



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# File 'lib/antlr4/atn/LexerATNSimulator.rb', line 23

def reset
    @index = -1
    @line = 0
    @column = -1
    @dfaState = nil
end