Date: Tue, 1 Jun 2004 14:21:16 -0400 From: Ronald J Kimball <[EMAIL PROTECTED]>
On Tue, Jun 01, 2004 at 02:11:56PM -0400, [EMAIL PROTECTED] wrote: > 13 '__pqr____xyz__pqr___abc___' =~ /(($re).*?)*(?!)/; > Of course, this is incomplete, but it is a start. One thing that > puzzles me is that the (?!) is absolutely required on line 13. > Without it, @seen doesn't get initialized at all. Why should this be? > I would have thought that the final '*' in the regexp would be enough > to get the regexp to continue attempting to match. /(anything)*/ can always match a zero length substring at the beginning of the string, and as soon as the regex engine finds a match, it stops. The (?!) forces the regex engine to backtrack through all possible matches. I can see how that would be the case if the modifier were *?, but with plain * I expect the engine to match greedily, and not stop at the first match. kj
