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Date: Sun, 8 Nov 2020 17:42:53 +0000
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Subject: Re: [PHP-DEV] [RFC] Support for <func>::function syntax
From: rowan.collins@gmail.com (Rowan Tommins)

On 08/11/2020 02:12, Larry Garfield wrote:
> There was some discussion earlier this year, although if memory serves it was in a thread whose name would not be helpful for searching.


Here it is: https://externals.io/message/108459

Some of the key points (not an exhaustive summary):

- Looking up a function's fully-qualified name would need to check at 
run-time for the function's existence, since there are two possibilities 
for any name that's not already fully-qualified ('foo' and 
'current\namespace\foo'). This is different from ::class which (in most 
cases) resolves the expression to a name at compile-time based on 
current imports, and can resolve to a completely non-existent name. 
There are cases where it resolves at run-time [see 
https://wiki.php.net/rfc/class_name_literal_on_object] but none have the 
case of "valid name but no such class defined", which would need to be 
handled for functions.

- There was some discussion about the usefulness of returning the name, 
or a callable object, or some way of providing both. Suggestions 
included adding two new syntaxes, ::function and ::closure; simplifying 
the creation of a callable object from a string; or returning an object 
from which the name could be retrieved.

- Should (and could) the new syntax work with methods as well, e.g. 
Foo::bar::function and $foo->bar::function. If foo::function returns a 
string, these would logically need to return 
['Fully\Qualified\Name\Of\Foo', 'bar'] and [$foo, 'bar'] respectively; 
if it (or a variant of it) returns a Closure, it would be the 
(optimized) equivalent of passing those to Closure::fromCallable.


Regards,

-- 
Rowan Tommins (né Collins)
[IMSoP]