Re: CVS directories in completion-ignored-extensions

[Stefan Monnier <monnier@iro.umontreal.ca>]

> To me it seems like the regexp cache could be improved by
> keeping a usage counter and a lru timestamp so frequently
> used regexps could be kept in the cache -- and the cache
> could grow dynamically to always hold the most frequently
> used regexps [with some hard upper limit of course].

A cheap way to approximate something like that is to keep a `hit' flag
indicating whether this cache entry has ever been re-used.  Upon GC remove
all entries for which `hit' is false and reset all `hit' flags to false.

I.e. only those entries that have been reused since the last GC survive.

> E.g. if I have a large number of regexps to split mail in gnus,
> it would be nice to keep all of those in the cache.

But of course a larger cache means slower lookup.


        Stefan "who likes the idea of explicit regexp-compilation to
                regexp-objects"