Module: Aurum::Engine::BasicTokenizationCapability

Defined in:
lib/aurum/engine/tokenization_facility.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#column ⇒ Object (readonly)

Returns the value of attribute column.



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# File 'lib/aurum/engine/tokenization_facility.rb', line 11

def column
  @column
end

#line ⇒ Object (readonly)

Returns the value of attribute line.



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# File 'lib/aurum/engine/tokenization_facility.rb', line 11

def line
  @line
end

Instance Method Details

#next_symbol ⇒ Object 



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# File 'lib/aurum/engine/tokenization_facility.rb', line 12

def next_symbol
  return @push_back.pop unless @push_back.empty?
  @recognized, @recognized_lexeme = nil, ''
  until @recognized          
    @lexeme, next_state, char = '', @states.last, nil
    lookaheads, action = [], nil
    while next_state
      if char
        lookaheads << char
        @column += 1
      end
      return EOF if @input.eof? && @recognized_lexeme.empty? && @lexeme.empty? && lookaheads.empty?
      state, char = next_state, @input.get_char
      if lexical_table.actions[state]
        action = lexical_table.actions[state]
        while (c = lookaheads.shift)
          @lexeme << c
        end
      end            
      next_state = goto(state, char)
    end
    @input.pushback char
    unless action
      unrecognized_lexeme = @recognized_lexeme
      lookaheads.each {|lookahead| unrecognized_lexeme << lookahead}
      return Token.new('$unknown', unrecognized_lexeme)
    end
    while (c = lookaheads.pop)
      @input.pushback c   
    end
    @recognized_lexeme += @lexeme unless action.token == '$ignored'
    shift_to(action.state) if action.state
    @recognized = Token.new(action.token, @recognized_lexeme) if action.token && action.token != '$ignored'
    instance_eval(&action.action) if action.action 
  end
  @recognized
end

#pushback(symbol) ⇒ Object 



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# File 'lib/aurum/engine/tokenization_facility.rb', line 50

def pushback symbol
  @push_back.push(symbol)        
end