# wide.rb
# by Kazuhiro Yoshida (moriq.kazuhiro@nifty.ne.jp)

module Wide
  def wide_at(string, index)
    i = 0
    string.scan(/(.)/) { |char,|
      break if i == index || i == index+1
      i+= char.size
    }
    i - index
  end
  module_function :wide_at

  def space?(dst, src)
    tail = if dst then /.$/ =~ dst; $& else nil end
    head = if src then /^./ =~ src; $& else nil end
    if tail && head
      if tail.size == 2 && head.size == 2
        false
      else
        true
      end
    else
      nil
    end
  end
  module_function :space?

end