Contents

module Treetop
  class Optional < OrderedChoice
    attr_reader :expression
    
    def initialize(optional_expression)
      super([optional_expression, TerminalSymbol.epsilon])
      @expression = optional_expression
    end
    
    def to_s
      "(#{expression.to_s})?"
    end    
  end
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
treetop-0.1.0	lib/treetop/grammar/parsing_expressions/optional.rb