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Date: Thu, 24 Jun 2021 11:44:17 +0200
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To: tyson andre <tysonandre775@hotmail.com>
Cc: "internals@lists.php.net" <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] clamp
From: michal.brzuchalski@gmail.com (=?UTF-8?Q?Micha=C5=82_Marcin_Brzuchalski?=)

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czw., 24 cze 2021 o 02:15 tyson andre <tysonandre775@hotmail.com>
napisa=C5=82(a):

> Hello Kim Hallberg,
>
> > The RFC for the clamp function is now open and under discussion, you no=
w
> have 2 weeks
> > to discuss, suggest improvements and open issues before voting is
> considered.
>
>
> From https://wiki.php.net/rfc/clamp -
>
> > Current userland implementations are handled in several ways, some of
> which use min and max to check the bound,
> > which is costly and slow when called often.
> > Because userland implementations are for the most part not
> cost-effective when called multiple times,
> > a language implementation is desired.
>
> I'd strongly prefer an actual benchmark for context and accuracy - is it
> actually faster or slower than the most efficient userland implementation
> and by how much?
> E.g. in an optimized NTS build with `CFLAGS=3D-O2`, opcache
> enabled(zend_extension=3Dopcache, opcache.enable=3D1,opcache.enable_cli=
=3D1),
> and no debug configure flags, how many calls per second can be made on
> variable values of $num for both?
> (I'd assume over twice as fast as calling both min/max from another
> function, but possibly slower than efficient_clamp, but haven't run this)
>
> For userland implementations that did use min/max, they probably weren't
> performance sensitive for the application.
>
> ```php
> function efficient_clamp(int|float $num, int|float $min, int|float $max):
> int|float {
>     return $num < $min ? $min : ($num > $max ? $max : $num);
> }
> ```
>

Do we really need it?
IMO the performance of this is not gonna change anything much.
We're talking about nanoseconds here possibly.

I'm looking forward to Hello World RFC - that's also often implemented in
userland.

```php
function hello(?string $who =3D 'World', bool $return =3D false, bool $newl=
ine
=3D true): ?string {
    $str =3D "Hello {$who}!" . ($newline ? PHP_EOL : '');
    if ($return) return $str;
    echo $str;
}
```

I get an impression that we constantly add things into standard library
which are from a language perspective irrelevant
and that all could be developed in userland with no harm.

Cheers,
--
Micha=C5=82 Marcin Brzuchalski

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