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To: Mike Schinkel <mike@newclarity.net>
CC: PHP internals <internals@lists.php.net>
Thread-Topic: [PHP-DEV] Proposal: Adding functions any(iterable $input,
 ?callable $cb = null, int $use_flags=0) and all(...)
Thread-Index: AQHWfj2/bRooGr39CkeRSgZBGY4s+alPjGGAgAArEDGAAHp9gIAAp0UT
Date: Sun, 30 Aug 2020 16:31:19 +0000
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Subject: Re: [PHP-DEV] Proposal: Adding functions any(iterable $input,
 ?callable $cb = null, int $use_flags=0) and all(...)
From: tysonandre775@hotmail.com (tyson andre)

Hi Mike Schinkel,=0A=
=0A=
> Doesn't the occasional required use of long constant names like ARRAY_FIL=
TER_USE_KEY and ARRAY_FILTER_USE_BOTH somewhat negative the benefit of a mo=
re concise syntax?  =0A=
> =0A=
> I know that many existing functions in PHP have a collection of long cons=
tant names that can be passed, but is that a style of programming that PHP =
really wants to continue to proliferate, or would it not be better to addre=
ss that use-case in a different manner?   (Admittedly doing so might requir=
e having this feature dependent on other critical path language features.)=
=0A=
> =0A=
> One approach might be if PHP could allow for skipped parameters in callab=
les =97 where I am using a single underscore to indicate an unused paramete=
r (GoLang has a "blank identifier" for similar purposes so there is some pr=
ior art to consider) =97 e.g:=0A=
> =0A=
> - the default is `any($iterable, fn ( $value ) =3D> ...)`=0A=
> - or `any($iterable, fn ( _, $key ) =3D> expr )`=0A=
> - or `any($iterable, fn ( $value, $key ) =3D> expr )`=0A=
>=0A=
> PHP could handle it more generically, is possible, or recognize this and =
branch to different implementations of any() and all() if the goal is to op=
timize performance by only passing one value in key-only or value-only call=
s.=0A=
> =0A=
> Optionally we could use null instead:=0A=
> =0A=
> - the default is `any($iterable, fn ($value) =3D> ...)`=0A=
> - or `any($iterable, fn (null, $key) =3D> expr )`=0A=
> - or `any($iterable, fn ($value, $key) =3D> expr )`=0A=
=0A=
Supporting "blank identifiers" is out of the scope of this RFC,=0A=
and would have some implementation concerns of how it'd work with named par=
ameters=0A=
and how backtrace generation would be affected. I don't think there'd be a =
significant performance improvement over not using parameters.=0A=
=0A=
I'm taking $flag out of the rfc because there's many proposed alternatives =
for doing this,=0A=
and checking values of an iterable is the most common use case.=0A=
=0A=
Repeating the response to Marco Pivetta,=0A=
I find that checking parameter counts would be inconsistent with how other =
internal functions accepting callbacks such as `array_filter` already behav=
e.=0A=
It would also be unexpected if users or tooling wrap callbacks with other c=
allbacks.=0A=
Developers would also expect `func_get_args()` to work.=0A=
=0A=
```=0A=
<?php=0A=
function my_none(iterable $values, callable $predicate) {=0A=
    return all($values, fn(...$args) =3D> $predicate(...$args));=0A=
}=0A=
// PHP can't distinguish between these when given `fn(...$args)`=0A=
// - would throw if passed 1 parameter=0A=
my_none($values, fn($value, $key) =3D> $value =3D=3D true || $key =3D=3D 'x=
');=0A=
// - would throw if passed 2 parameters (too many)=0A=
my_none($values, 'is_string');=0A=
```=0A=
=0A=
Cheers,=0A=
- Tyson=0A=