--- insert(nth, other)  ruby 1.7 feature

    nth ܤʸľʸ other ޤ
    ʲ(ͤ)ƱǤ

        self[nth, 0] = other

    self ֤ޤ

        str = "foobaz"
        p str.insert(3, "bar")
        # => "foobarbaz"

