: skip( pattern: Regexp )  ->  Integer
    ݥ󥿤 PATTERN ʸΥޥåޤ
    ޥå饹ݥ󥿤ʤޥåʬʸ
    Ĺ֤ޤޥåʤä nil ֤ޤ

        s = StringScanner.new('test string')
        p s.skip(/\w+/)   #=> 4
        p s.skip(/\w+/)   #=> nil
        p s.skip(/\s+/)   #=> 1
        p s.skip(/\w+/)   #=> 6
        p s.skip(/./)     #=> nil

