Help for this page

Select Code to Download


  1. or download this
    /^(?(?=((?(3)(?(?!.*\3)(?(?!((?<=(?!\3).(?=(?2)).
|(?=\3)..)))(*F))))(?(?=.)(?=(.)(?1)))))(*F))/sx
  2. or download this
    qr{
    (?(DEFINE) (?<loopfwd>
...
        (?{ print "loopfwd didn't match (single found)\n" })
    )
}msx