module StringDirection
  # @abstract Subclass and override {#run} to implement
  class Strategy
    # Each strategy must implement this method, accepting an string as its argument. It must return {StringDirection::LTR}, {StringDirection::RTL}, {StringDirection::BIDI} depending on direction detected, or nil on detection failure
    # @abstract
    # @raise [NotImplementedError]
    def run(string)
      fail NotImplementedError, "`run` method must be implemented"
    end

    private

    def ltr
      StringDirection::LTR
    end

    def rtl
      StringDirection::RTL
    end

    def bidi
      StringDirection::BIDI
    end
  end
end