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Date: Thu, 25 Feb 2016 20:28:08 +0000
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Subject: Re: [PHP-DEV] Re: [RFC] Callable constructors
From: rowan.collins@gmail.com (Rowan Collins)

On 25/02/2016 17:40, Andrea Faulds wrote:
> Dan Ackroyd wrote:
>> I've written a small RFC to make it possible to call constructors of
>> objects as a callable, rather than only being able to call them
>> through the 'new' language construct.
>>
>> https://wiki.php.net/rfc/callableconstructors
>
> While I like the concept, I dislike the execution. 

Snipped for brevity, but I agree with your sentiment here. Making 
__construct more magic seems like an imperfect solution to this. I'm not 
sure making a new magic method (new, __new, etc) is much better though, 
since it would serve such a limited purpose.

It has come up before in various contexts that PHP lacks a true callable 
type, in the sense that you never "construct" a callable, you just *use* 
something as a callable. I think callable constructors would fit better 
as part of an API that solved this.

For instance, there could be a (magic) Callable class with various named 
constructors:

- Callable::forFunction(string $function_name)
- Callable::forMethod(object $instance, string $method_name)
- Callable::forStaticMethod(string $class_name, string $method_name)
- Callable::fromPaamayimNekudotayim(string $class_colon_colon_method) // 
OK, maybe not ;)

This isn't perfect, because the parameters would still look like strings 
to static analysis, rather than being proper compiled-in references, but 
it's nicer than repeatedly analysing an array or string to evaluate 
is_callable() or type-checks.

Then we could add to that a special case for constructors:

- Callable::forConstructor(string $class_name)

This would be roughly equivalent to (and polyfillable with):

return function (...$args) use ( $class_name ) { return new $class_name(...$args); };


Regards,

-- 
Rowan Collins
[IMSoP]