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Date: Mon, 21 Dec 2020 17:15:16 -0500
In-Reply-To: <94748D59-630B-4EE2-8106-B68AA4E449D2@benramsey.com>
Cc: "internals@lists.php.net" <internals@lists.php.net>,
 Ben Ramsey <ben@benramsey.com>
To: tyson andre <tysonandre775@hotmail.com>
References: <DM6PR07MB6618468A8C4A49818C4E2EB0F9C10@DM6PR07MB6618.namprd07.prod.outlook.com>
 <94748D59-630B-4EE2-8106-B68AA4E449D2@benramsey.com>
Subject: Re: [PHP-DEV] [RFC] Add is_list(mixed $value): bool to check for
 list-like arrays
From: mike@newclarity.net (Mike Schinkel)

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> On Dec 20, 2020, at 9:09 PM, Ben Ramsey <ben@benramsey.com> wrote:
>=20
>> On Dec 19, 2020, at 19:43, tyson andre <tysonandre775@hotmail.com>
>> wrote:
>>=20
>> It can be useful to verify that the assumption that array keys are
>> consecutive integers is correct, both for data that is being passed
>> into a module or for validating data before returning it from a
>> module. However, because it's currently inconvenient to do that, this
>> has rarely been done in my experience.
>=20
> I think there are some places where `is_list()` could be unintuitive =
to
> those who don=E2=80=99t understand some of the idiosyncrasies of PHP.
>=20
> For example, with
>=20
>    $a =3D ['foo', 'bar', 'baz=E2=80=99];
>=20
> `is_list()` will return `true`, but if you run `$a` through `asort()`,
> `is_list()` will return `false` because the keys are no longer
> consecutive integers, but is there any doubt this is still a list?
> Maybe in a pure sense, it=E2=80=99s not, but I think this could be =
confusing.
>=20
> But now, if we do
>=20
>    $b =3D array_merge($a, ['qux', 'quux']);
>=20
> `$b` is now back to being a list, so `is_list($b)` returns `true`.
>=20
> While I understand the convenience `is_list()` provides--I myself have
> implemented the opposite of this numerous times (e.g.,
> `is_dict()`)--it comes close to implying a data type that PHP =
doesn=E2=80=99t
> have, and I think this could give a false sense of type-safety-ness
> when using this function to check whether something is a 0-indexed
> array.
>=20
> Cheers,
> Ben
>=20

Would either is_zero_based() or is_zero_indexed() be a reasonable name =
instead?

-Mike

P.S. See https://en.wikipedia.org/wiki/Zero-based_numbering =
<https://en.wikipedia.org/wiki/Zero-based_numbering>


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