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Message-ID: <4DAE13E9-5C10-42DC-A7BE-48A54B734520@gmail.com>
Cc: "pierre@pcservice.co.za" <pierre@pcservice.co.za>,
 Thomas Bley <thbley+php@gmail.com>,
 PHP Development <internals@lists.php.net>,
 Daniele Orlando <dnl.rlnd@gmail.com>
Date: Mon, 18 Mar 2013 18:49:26 +1100
To: =?utf-8?Q?Mat=C4=ABss_Roberts_Treinis?= <mrtreinis@gmail.com>
Subject: Re: [PHP-DEV] __invokeStatic() method
From: davidkmuir@gmail.com (David Muir)

On 18/03/2013, at 6:07 PM, Mat=C4=ABss Roberts Treinis <mrtreinis@gmail.com>=
 wrote:

> Not only that. This potentially might break compatibility with many
> software products already out there. Also, this might lead to many
> misunderstandings and, in fact, ambiguous code. Consider the sample.
>=20
> $name =3D 'something';
> $something =3D $name(); // What is this - a function call or object?
>=20
> Fact is, we can not know that unless a) do a search in code b) var_dump?
>=20
>=20
> 2013/3/18 Pierre du Plessis <pierre@pcservice.co.za>
>=20
>> On Mar 18, 2013 2:41 AM, "Thomas Bley" <thbley+php@gmail.com> wrote:
>>>=20
>>> On Sat, Mar 16, 2013 at 9:33 PM, Pierre du Plessis
>>> <pierre@pcservice.co.za> wrote:
>>>> On Mar 16, 2013 9:35 PM, "Daniele Orlando" <dnl.rlnd@gmail.com> wrote:
>>>>>=20
>>>>> Hi List,
>>>>>=20
>>>>> I'm interested in proposing an RFC and I would know your opinion.
>>>>>=20
>>>>> =3D=3D=3D Current Situation =3D=3D=3D
>>>>> Since PHP 5.3 we can use an object instance, who defines the
>> __invoke()
>>>>> method, as a callable object.
>>>>> Example:
>>>>>=20
>>>>> // PHP Code.
>>>>> class Runnable
>>>>> {
>>>>>    public function __invoke()
>>>>>    {
>>>>>        echo "Runned";
>>>>>    }
>>>>> }
>>>>>=20
>>>>> $r =3D new Runnable();
>>>>> $r();
>>>>>=20
>>>>> // Output
>>>>> Runned
>>>>>=20
>>>>> =3D=3D=3D The Idea =3D=3D=3D
>>>>> In Python, when you construct an object, you don't need to use the
>> "new"
>>>>> keyword but you just invoke the class name followed by "()", like the
>>>> class
>>>>> is a function.
>>>>> Example:
>>>>>=20
>>>>> // Python Code.
>>>>> class A:
>>>>>    pass
>>>>>=20
>>>>> A()
>>>>>=20
>>>>> // Output.
>>>>> <__main__.A instance at %address>
>>>>>=20
>>>>> Now, would be interesting to extend the PHP __invoke() method adding
>> an
>>>>> __invokeStatic() method, like happens with __call() and __callStatic()=

>>>>> methods.
>>>>> In this way could be possible to use a class name to invoke the
>>>>> __invokeStatic() method.
>>>>> Example:
>>>>>=20
>>>>> // PHP Code.
>>>>> class TrueRunnable
>>>>> {
>>>>>    public static function __invokeStatic()
>>>>>    {
>>>>>        echo "Runned";
>>>>>    }
>>>>> }
>>>>>=20
>>>>> TrueRunnable();
>>>>>=20
>>>>> // Output.
>>>>> Runned
>>>>>=20
>>>>> But the possibility are endless:
>>>>>=20
>>>>> class A
>>>>> {
>>>>>    public static function __invokeStatic()
>>>>>    {
>>>>>        return new A();
>>>>>    }
>>>>>    public method m() {}
>>>>> }
>>>>>=20
>>>>> A()->m();
>>>>>=20
>>>>> // or
>>>>>=20
>>>>> class A
>>>>> {
>>>>>    private $_instance;
>>>>>    public static function __invokeStatic()
>>>>>    {
>>>>>        // Singleton pattern.
>>>>>        if (self::$_instance) {
>>>>>            return self::$_instance;
>>>>>        }
>>>>>=20
>>>>>        return self::$_instance =3D new A();
>>>>>    }
>>>>>    public method m() {}
>>>>> }
>>>>>=20
>>>>> A()->m();
>>>>>=20
>>>>>=20
>>>>> =3D=3D=3D Conclusion =3D=3D=3D
>>>>> This feature makes the __invoke() method consistent with the __call()
>> and
>>>>> __callStatic() methods,
>>>>> and opens the door to many cool stuff.
>>>>>=20
>>>>> Any feedback is appreciated.
>>>>>=20
>>>>> Daniele Orlando
>>>>=20
>>>> I don't really see a use case for this, as you can already use the
>> syntax
>>>> A::method();
>>>>=20
>>>> E.G class A { public static function invoke() { return new A; }
>>>>=20
>>>> public function m() { echo 'Runned'; }
>>>>=20
>>>> A::invoke()->m();
>>>>=20
>>>> Your example above only saves a few characters to type and can lead to
>> a
>>>> lot of problems if you have a function with the same name as the class.=

>>>=20
>>> Using A::invoke(), you need to know the name of "invoke()" and it's
>>> hard to force users always to use the invoke() function.
>>> Using A() would be more clean since all the static init(), factory(),
>>> invoke(), getInstance() are gone.
>>> Having __call(), __callStatic(), __invoke() and invokeStatic() would
>>> make the overloading concept more consistent.
>>>=20
>>> Regards,
>>> Thomas
>>>=20
>>> --
>>> PHP Internals - PHP Runtime Development Mailing List
>>> To unsubscribe, visit: http://www.php.net/unsub.php
>>=20
>> Using A() looks too much like a function call. And there is still the iss=
ue
>> with having a function name the same as the class name.
>>=20

This works well in languages like JavaScript where functions are objects.
As much as I like the feature there, I'm not sure it's a great fit for PHP.

David

Sent from my iPhone=