On Wed, Jul 18, 2007 at 11:24:40PM +0200, Carsten Dominik wrote: > On Jul 16, 2007, at 15:21, Adam Spiers wrote: > >There seem to be a number of hardcoded regexps currently used for > >matching heading tags, all very similar looking, and typically > >something like: > > > > [ \t]*\\(:[[:alnum:]_@:]+:\\)?[ \t]*\\($\\|\r\\) > > > >Is there any reason why these shouldn't be factored out into a new > >defcustom org-tags-regexp? > > Well, one reason is efficiency. When a regular expression is a > constant, > Emacs is able to cache the compiled version of the regular expression, > and this can speed up code that does a lot of matching quite a bit. The > token you show above is usually part of a larger string, so the full > regular expression would have to be make with concat and will therefore > be recompiled all the time.
Right, point taken - like m//o in Perl. To be honest, it doesn't matter too much to me if it's defconst rather than defcustom. The main thing is that I can have tags starting with '<' :-) I suggest that we start by refactoring into a defconst, and then we can worry about turning that into a defcustom in a way which retains efficiency at a later date - if anyone needs the defcustom badly enough. Makes sense? Cheers, Adam _______________________________________________ Emacs-orgmode mailing list Emacs-orgmode@gnu.org http://lists.gnu.org/mailman/listinfo/emacs-orgmode
