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Date: Sat, 27 Feb 2016 18:56:04 +0000
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Subject: Re: [PHP-DEV] [RFC] Callable constructors
From: rowan.collins@gmail.com (Rowan Collins)

On 26/02/2016 17:08, Dan Ackroyd wrote:
> Rowan Wrote:
>> I would like to join Adam in asking if
>> you can find examples in other languages where constructors can be used
>> as though they were static methods in this way.
> Python would be a good example. constructors are just functions that
> can be called, and passed around as 'callable' things.
>
> Obviously Pythons concepts of classes aren't identical to PHP'
> concepts - but the code is doing the same thing; passing around a
> thing that can be called without having to use Reflection to make it a
> callable.
>
>
> http://goo.gl/SnTNZH

Looking at your example at first, I couldn't see how it demonstrated any 
such passing, because you can dynamically select class names in PHP 
(here's that code transposed line-by-line to PHP): https://3v4l.org/AD2m3

Looking closer, that's not actually what's happening, but it's still not 
equivalent to what you want in PHP:

- The first difference is that "Foo()" rather than "new Foo()" creates 
an object; the fact that "Foo" is a class rather than a function causes 
this to happen when it is invoked. This is different from PHP, where 
classes and functions don't share a namespace, and a class is not 
something that can be invoked ("foo()" doesn't refer to the same thing 
as "new foo()").
- The second difference is that you are not passing around a string 
representing what to call, but a reference to the invokable object 
itself. The line "classname = Foo" simply makes "classname" an alias for 
the class "Foo", which is then invokable as before to trigger instantiation.

So if anything, this particular example is more like my 
Callable::forConstructor() idea - a way of passing around an invokable 
object which, when invoked, will cause instantiation of a particular class.

I don't, however, know Python well enough to say whether a better 
example would be more like what you want in PHP.

Regards,

-- 
Rowan Collins
[IMSoP]