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Date: Wed, 22 Apr 2020 01:42:03 +0300
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To: Matthew Brown <matthewmatthew@gmail.com>
Cc: Internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Any interest in a list type?
From: maxsem.wiki@gmail.com (Max Semenik)

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On Tue, Apr 21, 2020 at 10:00 PM Matthew Brown <matthewmatthew@gmail.com>
wrote:

> Why "list" and not "vec" or similar? "list" is also a reserved word =E2=
=80=93 I'm
> imagining that you'd construct a list like
>
> $l =3D list["a", "b", "c"];
>

"List" usually means linked list, "vector" would be much clearer and
consistent with many other languages


> I imagine such a "list" type would be a subtype of "array" =E2=80=93 ever=
ywhere
> that array was accepted, a list would be also, and it would have the same
> copy-on-write behaviour.
>
> If people are interested in having that type, there's a question of what =
to
> do with
>
> $some_list["a"] =3D 5;
>
> Would you convert the $some_list to an array, or throw an exception?
> Converting to an array would seem the more PHP-like thing to do.
>
> Similarly, the behaviour of
>
> $some_list[$key_out_of_current_range] =3D 5
>
> would be a matter of debate too =E2=80=93 would that turn $some_list into=
 an array,
> or would it fill up any preceding entries in the array with null?
>

I personally would prefer as little implicit magic as possible. Just throw
exceptions instead of allowing people to accidentally shoot themselves on
the foot.

What other questions are there? Is a "list" type even a good fit for PHP,
> given most of its users seem pretty content with the current
> swiss-army-knife array type?


If we're to dream about some bright distant future of data structures, my
dream would be to have a set of structures that make their big O behavior
clear, =C3=A0 la C++ STL or many other languages' standard libraries. Some =
of
them are already present in SPL, but notably not what you're proposing.
Additionally, it would be wonderful to have generic versions, e.g.
List<int> would not just accept only ints, but would store them internally
as zend_long, avoiding the overhead of zvals.

>
--=20
Best regards,
Max Semenik

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