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Date: Wed, 12 Feb 2020 22:47:24 +0000
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Subject: Re: [PHP-DEV] [RFC]
From: rowan.collins@gmail.com (Rowan Tommins)

On 12/02/2020 03:58, Mike Schinkel wrote:
> Returning a_closure_  instead of a string would be providing a feature we_already_  have instead of one we do_not_  have.


Not really, because you still need a way to get the fully-qualified name 
of the function. This is not valid:

namespace MyVendor\Something\Foo;
function bar() {}

\Closure::fromCallable('bar'); # Error: tries to resolve function '\bar'


So if we had ::function which returned the name, and ::callable that 
returned a closure, the following would be equivalent:

namespace MyVendor\Something\Foo;
function bar() {}

\Closure::fromCallable('MyVendor\Something\Foo\bar');
\Closure::fromCallable(bar::function);
bar::callable;


One combination would be ::function returning a string, and $() 
accepting one, which would give:

$(bar::function)


In practice, that would almost certainly be optimised into one 
instruction, so the main advantage would be consistency, unless there 
are use cases where a string rather than "any callable" is actually 
required.


> Or today just use fn() => myfunc().


That's not quite the same either: at the very least, you need to define 
it as fn(...$args) => myfunc(...$args) to pass through the parameters. 
But Closure::callable is able to copy the signature of the original 
function, including type information [1], so our hypothetical ::callable 
could do the same.


[1] https://3v4l.org/XBOmJ

Regards,

-- 
Rowan Tommins (né Collins)
[IMSoP]