Re: Regular expression performance in emacs, number of cached regexps

[wmperry@aventail.com (William M. Perry)]

Dale Hagglund <rdh@best.com> writes:

> Maybe adding a new function along the lines of
> 
> 	(re-compile REGEXP)
> 
> that returns a compiled form of REGEXP would be a useful approach.  Along
> with this, all the various regexp search functions could check if they're
> given a compiled or an uncompiled regexp, and either check the cache and
> compile if necessary, or just use the given compiled form.
> 
> This would let authors of regexp-heavy code pre-compile their own
> regexps, avoiding the entire issue of cache size.  The down-side of this
> is that over-zealous use of this could chew quite a bit of space in
> compiled regexps.
> 
> Is there some reason why this sort of approach is a bad idea?  I've used
> emacs extensively for many years, and written a fair amount of lisp code,
> but I'm only looked at the C internals a few times.

  This is actually something that is on my todo list, but I have zero free
time right now due to my mother's illness, so its been on the back burner
for a while.

-bill p.