--- Integer(arg)

    (Fixnum,Bignum)Ѵ̤֤ޤ
    ͡ʸʳΥ֥ȤФƤ to_i ᥽åɤ
    Ѥޤ(ruby 1.7 feature: 1.7 Ǥϡto_int)
    Ѵ̤(IntegerΥ֥饹)Ǥʤ
    㳰 TypeError ȯޤ

    ʸǤäˤϡ0x, 0b, 0 ʤɤƬ˱
    줾 16 ʡ2 ʡ8 ʿȤѴޤ

    ȸʤʤʸ˻ꤷ硢㳰 ArgumentError
    ȯޤ
    String#hex [String/hex],
    String#oct [String/oct],
    String#to_i [String/to_i] ⻲ȤƤ

