Friday afternoon blag fest

Denny at
Fri Sep 21 13:37:33 BST 2007

On Fri, 2007-09-21 at 13:11 +0100, Chris Jack wrote:
> What's the longest regular expression anyone's ever written? Choose
> your own criteria for longest (e.g. #lines, #characters) although I
> suspect pitifully slow might get less respect from the audience....

A place I used to work had their own 'web application framework' and
template processing engine.  At the core of the latter lay a regular
expression too large to fit into a sane terminal size in any direction.
When we upgraded from Perl 5.6 to Perl 5.8 all our sites and servers
suffered a slowdown in the region of 80 times (8000%).  That wasn't a
particularly fun day.

Fortunately the guy who wrote said engine and said regex happened to be
in the company offices at the time doing some contracting work, so he
got stuck with fixing it  :)  (it turned out to be something to do with
a change in how backreferencing is dealt with, iirc)

More information about the mailing list