[Python-ideas] re.compile_lazy - on first use compiled regexes

[Antoine Pitrou]

On Sat, 23 Mar 2013 16:48:47 -0700
"Gregory P. Smith" <greg at krypto.org> wrote:
> On Sat, Mar 23, 2013 at 4:34 PM, Bruce Leban <bruce at leapyear.org> wrote:
> 
> >
> > On Sat, Mar 23, 2013 at 4:14 PM, Gregory P. Smith <greg at krypto.org> wrote:
> >
> >> keep=True defeats the purpose of a caching strategy.  An re.compile call
> >> within some code somewhere is typically not in a position to know if it is
> >> going to be called a lot.
> >>
> >> I think the code, as things are now, with dynamic construction at runtime
> >> based on a simple test is the best of both worlds to avoid the more
> >> complicated cost of calling re.compile and going through its cache logic.
> >>  If the caching is ever is improved in the future to be faster, the code
> >> can arguably be simplified to use re.search or re.match directly and rely
> >> solely on the caching.
> >>
> >> ie: don't change anything.
> >>
> >>
> > Truth is people are currently doing caching themselves, by compiling and
> > then keeping the compiled regex. Saying they're not in a position to know
> > whether or not to do that isn't going to change that. Is it worthwhile
> > having the regex library facilitate this manual caching?
> >
> 
> In the absense of profiling numbers showing otherwise, i'd rather see all
> forms of manual caching like the conditional checks or a keep=True go away
> as it's dirty and encourages premature "optimization".

Agreed.

Regards

Antoine.