class Predicate
  module Native
    include Expr

    def priority
      90
    end

    def proc
      self[1]
    end

    # overriden because parent relies on free_variables,
    # which raises an exception
    def and_split(attr_list)
      # I possibly make references to those attributes, so
      # I can't be P2
      [ self, tautology ]
    end

    # overriden because parent relies on free_variables,
    # which raises an exception
    def attr_split
      { nil => self }
    end

    def to_ruby_code(scope = 't')
      if proc.respond_to?(:source_code)
        code = proc.source_code
        return code if code
      end
      raise NotSupportedError
    end

    def to_proc(scope = 't')
      proc
    end

    def free_variables
      raise NotSupportedError
    end

  end
end