From: Simon Strandgaard <neoneye@...>
Date: 2006-12-27T20:48:20+09:00
Subject: Re: reg exp comparison hanging irb

On 12/27/06, gaurav bagga <gaurav.v.bagga@gmail.com> wrote:
> can you explain regexp has nested repeating patterns.

the pattern  /a+/ is not nested.
putting ( )+ around it, then /(a+)+/ is nested 1 level.
putting ( )+ around it, then /((a+)+)+/ is nested 2 levels.

I suspect the GNU regexp engine sometimes go crazy when there
is a pattern that can match _nothing_ inside a nested pattern.

by matching _nothing_ i mean: ^ $ \b * ? lookahead lookbehind.. etc

-- 
Simon Strandgaard
http://opcoders.com/