You're right, the regexps was too simple. I updated the test with longer and more complex expression and the time is still the same.
I agree about caching regexps that are re-used in many places, obviously. Not so much about one-time expressions or strings. I'm really aware of how the different interpreters work, but it seems to me that immutable literals (strings, numbers, regexps) are the first thing I'd cache in a constant. Maybe current interpreters do that already internally ? On Mon, Jul 20, 2009 at 12:56 PM, John Resig <jere...@gmail.com> wrote: > It has less to do with RegExps and more to do with inline objects. You'll > note that I also moved inline functions out and declared them above. I'd, > eventually, like to do the same with inline arrays and object literals. > RegExp, Function, Array, and Objects shouldn't be re-declared on every > function call (or on every iteration in a loop!). > > While very-simple RegExp optimizations may be a wash, performance-wise, (I > note that your test regexp is only against a couple characters and doesn't > even use a capturing expression) the code simplification and minification > benefits are very real. Going through this process I was able to remove a > large number of duplicate RegExp - and that's always a good thing. > > --John > > > On Mon, Jul 20, 2009 at 9:20 AM, Ariel Flesler <afles...@gmail.com> wrote: > >> >> Hi >> >> I've been seeing the multiple commits for >> http://dev.jquery.com/ticket/4111. >> Moving regexps to local vars to cache them. >> >> I was wondering if this is a perfomance measure and if so, if there's >> some benchmark out there to prove the gain. >> I personally think these changes make the code more complicated and >> longer. I'd rather see the regexp in place if I want to understand >> what it does. >> >> I went ahead and created a benchmark for this: >> http://benchmarker.flesler.com/regexp/run/ >> >> The conclusions were that there's absolutely no gain in speed except >> on IE. Even on IE, it doesn't seem to be such a critic improvement and >> it's slower the more you get away from the variables' scope chain (in >> nested functions). >> >> Any opinion ? >> >> Cheers >> -- >> Ariel Flesler >> >> > > > > -- Ariel Flesler http://flesler.blogspot.com --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "jQuery Development" group. To post to this group, send email to jquery-dev@googlegroups.com To unsubscribe from this group, send email to jquery-dev+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/jquery-dev?hl=en -~----------~----~----~----~------~----~------~--~---
