StringRegExp that I don't understand

[Paulie 26]

I just "Stumbled Upon" this Regular Expression that seems to be able to tell if a number is prime.

I piped it into autoit, and it seems to work!

Unfortunately, due to my limited knowledge of StringRegExp, I find myself unable to understand exactly how it works, and i was wondering if one of the RegExp Gurus here could give me an explanation of the logic behind it.

Func _IsPrime($Integer)
    $String = ""
    For $i = 1 to Number($Integer)
        $String&="1"
    Next
    If Not StringRegExp($String,"^1?$|^(11+?)\1+$") Then
        Return 1
    Else
        Return 0
    EndIf
EndFunc

Edited September 29, 2007 by Paulie

[Paulie 26]

I have a feeling that i have managed to fugure at least the vast majority of this one out by myself.

Now that i understand the concept of "Backtracking" it all makes sense.

Thanks