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Date: Thu, 20 Dec 2007 09:43:35 +0000
Reply-To: RQuadling@GoogleMail.com
To: "Alexey Zakhlestin" <indeyets@gmail.com>
Cc: "Stanislav Malyshev" <stas@zend.com>, 
	"troels knak-nielsen" <troelskn@gmail.com>, internals@lists.php.net
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References: <98b8086f0712150818n40056cedyf0aae7a5a08a27b7@mail.gmail.com>
	 <200712172130.08216.larry@garfieldtech.com>
	 <4FADC266-873E-4FD2-BEC8-28EA9D833297@procata.com>
	 <200712172341.54372.larry@garfieldtech.com>
	 <98b8086f0712191345h7fe11a7kc5d34b0369754c8f@mail.gmail.com>
	 <47699960.1090101@zend.com>
	 <98b8086f0712191528n2fd348d0oe3da9eed20d87194@mail.gmail.com>
	 <4769ACF5.7000701@zend.com>
	 <cd5680a20712192257p1a10a488ub0dc61a512d3341f@mail.gmail.com>
Subject: Re: [PHP-DEV] Re: PATCH: anonymous functions in PHP
From: rquadling@googlemail.com ("Richard Quadling")

On 20/12/2007, Alexey Zakhlestin <indeyets@gmail.com> wrote:
> On 12/20/07, Stanislav Malyshev <stas@zend.com> wrote:
> > > I think we need it. In the current incarnation, anonymous functions
> > > are so impractical to use, that it's a barrier. I think that is
> > > unfortunate, because it could be an interesting and useful direction
> > > to take for PHP. The users, who don't know what a closure is, could
> >
> > Direction like what?
>
> being able to do the following (and not to worry about runtime
> compilation) is a good reason on it's own:
>
> array_filter($my_data, function($test){ return 3 === ($test % 4) });

That makes perfect sense to me as I see/use this sort of code in JavaScript.

The argument about making the filter a global function is not sensible
to apply in all circumstances. In many cases the filter is only going
to be of use in an array_filter() call, so now we would have 2
functions to do the work of 1.

If you think about for() and foreach(), these are functional-ish
ideas. Iterators in general should quite happily support this idea.

Maybe a syntax like this would be more appealing ...

array_filter($my_data as $test) {
  return 4 === ($test % 4);
}

This sort of looks like a foreach, which is extremely readable.

Richard.

-- 
-----
Richard Quadling
Zend Certified Engineer : http://zend.com/zce.php?c=ZEND002498&r=213474731
"Standing on the shoulders of some very clever giants!"