Hi Larry Garfield,
> > Hi Larry Garfield,
> >
> > > > Hi internals,
> > > >
> > > > Voting has started on https://wiki.php.net/rfc/any_all_on_iterable and
> > > > ends on 2021-02-22.
> > > >
> > > > This RFC proposes to add the functions `PHP\iterable\any(iterable
> > > > $input, ?callable $callback = null): bool` and `PHP\iterable\all(...)`
> > > > to PHP's standard library's function set, using the namespace preferred
> > > > in the previous straw poll.
> > > >
> > > > There is a primary vote on whether to add the functions, and a
> > > > secondary vote on the name to use within the `PHP\iterable` namespace.
> > > >
> > > > Thanks,
> > > > - Tyson
> > > > --
> > > > PHP Internals - PHP Runtime Development Mailing List
> > > > To unsubscribe, visit: https://www.php.net/unsub.php
> > >
> > >
> > > Ak! I literally just finished reading it and wanted to note a lack of
> > > clarity on one point. :-)
> > >
> > > The signature of the callback is never specified explicitly. The ternary
> > > is a bit confusing. I assume the signature is
> > >
> > > callable(mixed): bool
> > >
> > > But that's not made explicit. It's also not made explict that omitting
> > > the callable collapses to "is truthy". That's a sensible thing to do,
> > > but it's not stated explicitly anywhere, just inferred from the code
> > > sample.
> > >
> > > I'm not sure if it's safe to clarify at this point as the vote just
> > > started.
> >
> > If there is a callable, it allows `callable(mixed): mixed`,
> > and converts the callable's return value to a boolean.
> > So omitting the callable is the same as passing in the callable `fn($x)
> > => $x`, which is equivalent to `fn($x) => (bool)$x`.
> > This is exactly what the reference implementation would do.
> >
> > I definitely should have clarified it instead of assuming that the
> > reference implementation was clear enough.
> >
> > I clarified this and gave examples because the RFC started a few hours
> > ago and the implementation didn't change.
>
> Oof. I'm glad I asked, because I don't like that at all. If available, the
> callable should be returning bool, not "anything that may be truthy/falsy."
> If you have an explicit function, it should have an explicit return type. A
> truthy check is a reasonable default, but not for when you're opting in to
> specifying the logic.
>
> I am in favor of the RFC, but I will have to consider if that changes my vote
> to No.
>
> --Larry Garfield
This was a deliberate choice and is consistent with the weak type comparison
behavior of array_filter() and other functions that default to using weak type
checks internally.
I'd agree that I'd prefer to see callbacks returning booleans in code I'm
reviewing,
but a truthiness check seems more practical and consistent with the rest of the
language
than throwing a TypeError or checking the predicate return value using `!==
true`
This was made to make PHP more widely accessible and free of surprises.
e.g. `(bool)array_filter($arr, $predicate)` can be safely converted to
`any($arr, $predicate)` without introducing a TypeError or behavior change.
```
php > var_dump(array_filter([-1,0,1], fn($x)=>$x));
array(2) {
[0]=>
int(-1)
[2]=>
int(1)
}
```
This is the same choice as many other dynamic languages that aren't compiled
ahead of time have made.
```
# python
>>> any([1])
True
>>> any([0])
False
# Ruby
irb(main):001:0> [nil].any?
=> false
irb(main):002:0> [false].any?
=> false
irb(main):003:0> !!0
=> true
irb(main):004:0> [0].any?
=> true
# JavaScript
> [0].some(x=>x)
false
> [1].some(x=>x)
true
```
It is currently possible to check if code is passing a callable returning
anything other than a boolean
to functions such as `array_filter()` using a wide variety of static
analyzers/tools, e.g. http://github.com/phan/phan
```
<?php
// Phan emits "PhanTypeMismatchArgumentInternal Argument 2 ($callback) is (fn)
of type Closure(int):int
// but \array_filter() takes callable(mixed):bool|callable(mixed,mixed):bool"
array_filter([1], fn (int $x): int => $x % 3);
```
Thanks,
-Tyson
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