--- slice!(nth[, len])
--- slice!(substr)
--- slice!(first..last)
--- slice!(first...last)
--- slice!(regexp[, nth])

    ꤷϰ(self[] [String/[]] )ʸ󤫤
    Ǽʬʸ֤ޤ

    ϰϳؤ nil ֤ޤ

    ruby 1.7 feature: slice!(regexp, nth) ϡversion 1.7 ʹߤ
    ѤǤޤ

