--- coerce(number)

    number ηʬľܱ黻Ǥ뷿Ѵ
    [number, self] Ȥ˳Ǽ֤ޤͥ
    λѱ黻Ҥ̾Ｋʬȱ黻Ǥʤ饹򥪥ڥɤȤƼ
     coerce ȤäƼʬȥڥɤѴǱ黻
    ޤ

