Class: DFAState

Inherits:
Object show all
Defined in:
lib/antlr4/dfa/DFAState.rb

Overview

/

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(state_number = nil, _configs = ATNConfigSet.new()) ⇒ DFAState 



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# File 'lib/antlr4/dfa/DFAState.rb', line 41

def initialize(state_number=nil, _configs=ATNConfigSet.new())
    if state_number.nil? then
      @stateNumber = -1
    else
      @stateNumber = state_number
    end
    self.configs = _configs
    # {@code edges[symbol]} points to target of symbol. Shift up by 1 so (-1)
    #  {@link Token#EOF} maps to {@code edges[0]}.
    self.edges = nil
    self.isAcceptState = false
    # if accept state, what ttype do we match or alt do we predict?
    #  This is set to {@link ATN#INVALID_ALT_NUMBER} when {@link #predicates}{@code !=null} or
    #  {@link #requiresFullContext}.
    self.prediction = 0
    self.lexerActionExecutor = nil
    # Indicates that this state was created during SLL prediction that
    # discovered a conflict between the configurations in the state. Future
    # {@link ParserATNSimulator#execATN} invocations immediately jumped doing
    # full context prediction if this field is true.
    self.requiresFullContext = false
    # During SLL parsing, this is a list of predicates associated with the
    #  ATN configurations of the DFA state. When we have predicates,
    #  {@link #requiresFullContext} is {@code false} since full context prediction evaluates predicates
    #  on-the-fly. If this is not null, then {@link #prediction} is
    #  {@link ATN#INVALID_ALT_NUMBER}.
    #
    #  <p>We only use these for non-{@link #requiresFullContext} but conflicting states. That
    #  means we know from the context (it's $ or we don't dip into outer
    #  context) that it's an ambiguity not a conflict.</p>
    #
    #  <p>This list is computed by {@link ParserATNSimulator#predicateDFAState}.</p>
    self.predicates = nil
end

Instance Attribute Details

#configs ⇒ Object

Returns the value of attribute configs.



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# File 'lib/antlr4/dfa/DFAState.rb', line 39

def configs
  @configs
end

#edges ⇒ Object

Returns the value of attribute edges.



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# File 'lib/antlr4/dfa/DFAState.rb', line 39

def edges
  @edges
end

#isAcceptState ⇒ Object

Returns the value of attribute isAcceptState.



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# File 'lib/antlr4/dfa/DFAState.rb', line 39

def isAcceptState
  @isAcceptState
end

#lexerActionExecutor ⇒ Object

Returns the value of attribute lexerActionExecutor.



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# File 'lib/antlr4/dfa/DFAState.rb', line 40

def lexerActionExecutor
  @lexerActionExecutor
end

#predicates ⇒ Object

Returns the value of attribute predicates.



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# File 'lib/antlr4/dfa/DFAState.rb', line 40

def predicates
  @predicates
end

#prediction ⇒ Object

Returns the value of attribute prediction.



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# File 'lib/antlr4/dfa/DFAState.rb', line 39

def prediction
  @prediction
end

#requiresFullContext ⇒ Object

Returns the value of attribute requiresFullContext.



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# File 'lib/antlr4/dfa/DFAState.rb', line 40

def requiresFullContext
  @requiresFullContext
end

#stateNumber ⇒ Object

Returns the value of attribute stateNumber.



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# File 'lib/antlr4/dfa/DFAState.rb', line 39

def stateNumber
  @stateNumber
end

Instance Method Details

#<=>(other) ⇒ Object 



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# File 'lib/antlr4/dfa/DFAState.rb', line 91

def <=>(other)
  self.configs <=> other.configs
end

#==(other) ⇒ Object 



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# File 'lib/antlr4/dfa/DFAState.rb', line 111

def ==(other)
  # compare set of ATN configurations in this set with other
  return true if self.equal?(other)
  other.kind_of?(DFAState) and self.configs==other.configs
end

#eql?(other) ⇒ Boolean

Two DFAState instances are equal if their ATN configuration sets are the same. This method is used to see if a state already exists.

<p>Because the number of alternatives and number of ATN configurations are finite, there is a finite number of DFA states that can be processed. This is necessary to show that the algorithm terminates.</p>

<p>Cannot test the DFA state numbers here because in ParserATNSimulator#addDFAState we need to know if any other state exists that has this exact set of ATN configurations. The #stateNumber is irrelevant.</p>



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# File 'lib/antlr4/dfa/DFAState.rb', line 108

def eql?(other)
    self == other
end

#getAltSet ⇒ Object

Get the set of all alts mentioned by all ATN configurations in this

DFA state.



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# File 'lib/antlr4/dfa/DFAState.rb', line 78

def getAltSet()
    alts = Set.new
    if not self.configs.nil?
        for c in self.configs do
            alts.add(c.alt)
        end
    end
    if alts.empty?
        return nil
    else
        return alts
    end
end

#hash ⇒ Object 



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# File 'lib/antlr4/dfa/DFAState.rb', line 94

def hash()
    self.configs.hash
end

#to_s ⇒ Object 



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# File 'lib/antlr4/dfa/DFAState.rb', line 117

def to_s
    StringIO.open do |buf|
        buf.write(self.stateNumber.to_s)
        buf.write(":")
        buf.write(self.configs.to_s ) 
        if self.isAcceptState then
            buf.write("=>")
            if self.predicates then
                buf.write(self.predicates.to_s)
            else
                buf.write(self.prediction.to_s)
            end
        end
        return buf.string
    end
end