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References: <4BDEC91F.9080305@easyflirt.com> <4BDEEEDA.1050806@cschneid.com>
Date: Tue, 4 May 2010 05:34:59 +0800
Message-ID: <k2jb9defe2f1005031434r120154f1y9f7b6a93118178c3@mail.gmail.com>
To: Christian Schneider <cschneid@cschneid.com>
Cc: "mathieu.suen" <mathieu.suen@easyflirt.com>, PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Re: Closure local return
From: datibbaw@php.net (Tjerk Anne Meesters)

On Mon, May 3, 2010 at 11:42 PM, Christian Schneider
<cschneid@cschneid.com> wrote:
> mathieu.suen wrote:
>> May be it could be interesting to have a syntax for returning from the
>> define scope.
>> For example.
>>
>> $findedElment =3D $myList->selectIfAbsent($fooo, function(){
>> =A0 =A0 return 'No item founded'; //Retrun from the define scope
>> })
>> //Do somthing with $findedElment
>
> I think you actually misunderstand the difference in
> http://en.wikipedia.org/wiki/Closure_%28computer_science%29#Differences_i=
n_semantics
>
> The way I read if the difference is wether it returns from the closure
> function or the surrounding function *calling* it. Not the *defining* sco=
pe.

Mathieu is right in that it would return from the defining scope, but
it's important to note that when the closure is called the function
that defined the closure is still on the stack.

Consider the following example:

function f() { return function() { return; } }
$c =3D f();
$c();

If the semantics of Smalltalk were to apply, this would give an error,
because it's impossible to return from f() when the closure is being
called.

>
> And no, it doesn't make sense in the PHP context IMHO.

I second that ;-) In terms of clarity I find that the ECMAScript
implementation is much clearer.

>
> - Chris
>
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>



--=20
--
Tjerk