On Sat, May 4, 2013 at 4:31 PM, Laruence <larue...@php.net> wrote:
> I made a RFC for this:
> https://wiki.php.net/rfc/second_arg_to_preg_callback
>
>
Note that giving meaning to an extra argument in existing callbacks
constitutes a small BC break in at least two cases:
1)
function myhandyfunction($v, $arg = 42) { .. }
preg_replace_callback([..., ...], "myhandyfunction", ..)
here $arg will no longer be 42 after this change.
2)
Most internal functions do not accept extra arguments, and thus will
suddenly raise a notice if used as callbacks.
It might be worth mentionning this in the RFC.
> thanks
>
>
>
>
> On Sat, May 4, 2013 at 10:28 PM, Laruence <larue...@php.net> wrote:
>
> >
> >
> >
> > On Sat, May 4, 2013 at 9:46 PM, Anthony Ferrara <ircmax...@gmail.com
> >wrote:
> >
> >> Laruence,
> >>
> >> > foreach ($replacements as $regex => $callback) {
> >> > > $str = preg_replace_callback($regex, $callback, $str);
> >> > > }
> >> > >
> >> >
> >> > So if there are 10 regex in the array, you will got 10 DO_FCALL. 10
> >> times
> >> > arguments accept, 10 times etc...
> >> >
> >> > and AS I already said: IT is inefficient. I personally can not accept
> >> it.
> >> >
> >> > thanks
> >> >
> >> >
> >> My initial reaction was that the difference in runtime is going to be so
> >> insignificant that it's the very definition of a micro-optimization
> >> between
> >> the two. And unless you're doing it millions of times in a hot-loop,
> it's
> >> never even going to be realized. I was going to reply to that effect.
> >>
> >> Then I decided to write a quick test.
> >>
> >> $count = 100;
> >>
> >> $start = microtime(true);
> >> for ($i = 0; $i < $count; $i++) {
> >> $str = "abc";
> >> $str = preg_replace_callback('/a/', function($a) { return
> >> strtoupper($a[0]); }, $str);
> >> $str = preg_replace_callback('/b/', function($a) { return
> >> strtoupper($a[0]); }, $str);
> >> $str = preg_replace_callback('/c/', function($a) { return
> >> strtoupper($a[0]); }, $str);
> >> $str = preg_replace_callback('/a/', function($a) { return
> >> strtolower($a[0]); }, $str);
> >> $str = preg_replace_callback('/b/', function($a) { return
> >> strtolower($a[0]); }, $str);
> >> $str = preg_replace_callback('/c/', function($a) { return
> >> strtolower($a[0]); }, $str);
> >> }
> >> echo "Completed in " . (microtime(true) - $start) . " Seconds\n";
> >>
> >> $start = microtime(true);
> >> for ($i = 0; $i < $count; $i++) {
> >> $str = "abc";
> >> $str = preg_replace(array(
> >> '/a/e',
> >> '/b/e',
> >> '/c/e',
> >> '/a/e',
> >> '/b/e',
> >> '/c/e',
> >> ),
> >> array(
> >> 'strtoupper(\'$1\')',
> >> 'strtoupper(\'$1\')',
> >> 'strtoupper(\'$1\')',
> >> 'strtolower(\'$1\')',
> >> 'strtolower(\'$1\')',
> >> 'strtolower(\'$1\')',
> >> ),
> >> $str
> >> );
> >> }
> >> echo "Completed in " . (microtime(true) - $start) . " Seconds\n";
> >>
> >> So basically, it's comparing the old behavior (one call to preg_replace)
> >> that you want to emulate, with what Nikita is suggesting.
> >>
> >> I ran it on 3v4l (http://3v4l.org/dRjtU) and the results were quite
> >> surprising. I was expecting the first to be slightly slower than the
> >> second. But the reality surprised me:
> >>
> >> Completed in 0.00076389312744141 Seconds Completed in 0.0012428760528564
> >> Seconds
> >>
> >> As it turns out, calling preg_replace_callback() multiple times is
> almost
> >> 50% faster than using a single call to preg_replace().
> >>
> >> It's likely due to the precompiled nature of closures, vs the
> compilation
> >> happening multiple times at invocation in the preg_replace /e case.
> >>
> >> But it's still worth noting that switching from the /e style to a more
> >> traditional preg_replace_callback implementation will get you a
> >> significant
> >> boost in performance of that.
> >>
> >> Now, keep in mind, we're talking 0.000005 seconds saved per "execution"
> >> (group of 6 replacements). So it's not likely to matter much or be worth
> >> worrying about...
> >>
> > Hey:
> > thanks for the benchmark, but please don't think it's useless just
> > because it's monior
> >
> > PHP is a web program language, let's think about a high trafiic site,
> > which get 100, 000, 000 pv perday.
> >
> > 100, 000, 000 * 0.0000005 = 500s perday
> >
> > and inefficent not always means performance only, in this case , you
> > need to define various functions for different regexs if you use loop
> style.
> >
> > and do you prefer array_walk or foreach when you try to iteraterly
> > process an array?
> >
> >
> > thanks
> >
> >>
> >> My $0.02 at least...
> >>
> >> Anthony
> >>
> >
> >
> >
> > --
> > Laruence Xinchen Hui
> > http://www.laruence.com/
> >
>
>
>
> --
> Laruence Xinchen Hui
> http://www.laruence.com/
>
--
Etienne Kneuss
http://www.colder.ch
