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Date: Sun, 5 Jan 2020 18:48:16 +0000
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Subject: Re: [PHP-DEV] Autoloading functions/consts without a performance
 impact
From: rowan.collins@gmail.com (Rowan Tommins)

On 05/01/2020 18:03, tyson andre wrote:
>> Yes, I'm saying that the autoloader should be called for each lookup, so
>> autoloading of Foo\strlen should come between checking if Foo\strlen is
>> defined, and checking if \strlen is defined.
> That would be the intuitive approach for a language,
> but as mentioned earlier,
> it would significantly harm performance of existing code for php 7
> (slightly without an autoloader, more with autoloaders),
> and I can't imagine that getting approved.


Yes, I'm fully aware of the downsides. I just think relaxing that 
constraint would lead to a horribly confusing language.


> I'd considered that option, but that introduces its own surprises,
> which I'd consider to have more frequent and significant impact on applications that start using this.
>
> namespace NS;
> function f1($x) {
>       return mb_strlen($x) + 1;
> }
> function f2($x) {
>       return \mb_strlen($x) * 2;
> }
>
> Calling f2() then f1() would work, but f1() then f2() would not work, because f1() wouldn't autoload.


True; again, it violates the user's expectation, which I think can be 
summed up this way:

- The autoloader for a function should run the first time that function 
would run if it was pre-defined.

That in turn stems from an even more fundamental expectation:

- An application using an autoloader should behave the same as one which 
defines all functions in advance.


The more I think about it, the more I think we should just be optimising 
for the case where everything *is* defined in advance. As far as I know, 
PHP's autoloading is an anomaly among programming languages, and maybe 
it has outlived its usefulness.


Regards,

-- 
Rowan Tommins (né Collins)
[IMSoP]