--- self << object

    object Ϥޤobject ʸǤʤˤϥ᥽
     to_s ѤʸѴޤself ͤȤ
    ΤǡʲΤ褦 << ϢȤȤǤޤ

      STDOUT << 1 << " is a " << Fixnum << "\n"

    Ϥ˼Ԥ㳰 Errno::EXXX ȯޤ

