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Message-ID: <200806200729.40623.larry@garfieldtech.com>
Subject: Re: [PHP-DEV] [PATCH] [RFC] Closures and lambda functions in PHP
From: larry@garfieldtech.com (Larry Garfield)

On Friday 20 June 2008, Lenar L=C3=B5hmus wrote:
> Hi,
>
> Rodrigo Saboya wrote:
>  >> function ($x, $y) ($a, $b, $c) {};
>  >
>  > This looks better
>  >
>  >> function ($x, $y) [$a, $b, $c] {};
>
> I think this looks even better:
>
> function ($x, $y) use ($a, $b, &$c) {};
>
> (one could use this syntax even for traditional functions to
> use variable copies/references from global scope - just an idea).
>
> my 2,
> L.

I am not sure if "use" is the clearest word to use there (wouldn't lexical=
=20
there make more sense?), but I think the latter is a good trade-off.  It=20
makes it explicit whether you're using by-ref or by-val passing semantics,=
=20
and the semantics and syntax are the same as for function parameters so=20
there's a very low wtf factor.  I still am not sure if re-using=20
the "function" keyword is going to cause confusion, though, especially if=20
what is being implemented becomes (as it seems like it may) effectively an=
=20
alternate object syntax. =20

As one of the Haskell list denizens commented, is there a potential for mem=
ory=20
leakage if lambdas implicitly import $this when defined within an object=20
method?  Javascript makes it very easy to create memory leaks via closures =
if=20
you're not very careful; I would be fine with requiring an explicit=20
declaration of $this if it helped avoid memory leaks.

(Even if not many people will use closures at first, I anticipate that they=
=20
will become more widely used over time by which point arguments such as "th=
ey=20
won't be used often enough for the memory issue to matter" will be false bu=
t=20
it will be too late to fix.  I don't think anyone has made that argument ye=
t,=20
but I'm trying to head it off before someone does. <g>)

=2D-=20
Larry Garfield			AIM: LOLG42
larry@garfieldtech.com		ICQ: 6817012

"If nature has made any one thing less susceptible than all others of=20
exclusive property, it is the action of the thinking power called an idea,=
=20
which an individual may exclusively possess as long as he keeps it to=20
himself; but the moment it is divulged, it forces itself into the possessio=
n=20
of every one, and the receiver cannot dispossess himself of it."  -- Thomas=
=20
Jefferson