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Date: Tue, 29 Dec 2009 03:01:23 +0100
Message-ID: <e666c3890912281801t7ed60f9emab0652fff1e9bd06@mail.gmail.com>
To: Clint Priest <cpriest@warpmail.net>
Cc: internals@lists.php.net
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Subject: Re: [PHP-DEV] is_array on objects with ArrayAccess or Iterator 
	implementations
From: colder@php.net (Etienne Kneuss)

Hi,

On Tue, Dec 29, 2009 at 1:27 AM, Clint Priest <cpriest@warpmail.net> wrote:
> Etienne Kneuss wrote:
>>
>> On Tue, Dec 29, 2009 at 12:04 AM, Clint Priest <cpriest@warpmail.net>
>> wrote:
>>>
>>> Unfortunately $x instanceOf ArrayAccess doesn't return true when $x is
>>> indeed an array.
>>
>> Making is_array return true for objects implementing ArrayAccess is a
>> bad idea, for two main reasons:
>>
>> 1) is_array is a type check, and we should still be able to
>> distinguish real arrays from objects
>
> That's true of course, definitely would need to be able to distinguish.
>
>> 2) ArrayAccess does not guarantee that an object will behave like an
>> array, (e.g. you won't be able to use sort() on an object implementing
>> ArrayAccess.
>
> I wonder if this is something that users would be expecting, that any
> function which took an array would also take an object that implements
> certain interfaces (such as ArrayAccess and perhaps Countable).
>
>> If, in your case, you want to accept both arrays and ArrayAccess
>> objects, I guess if (is_array($v) || $v instanceof ArrayAccess) =A0is a
>> sufficiently good way to check.
>>
>
> I'm finding myself implementing ArrayAccess more and more often because i=
ts
> so transparent to the consumer. =A0The reason this came up is because I w=
as
> considering returning all arrays from a certain section of my shared code
> library always be an array object so that things like
> $tblArray->pluck('Value') could be done, rather than array_pluck() type
> functionality.
>
> That got me to thinking about all of the is_array() calls I would need to
> replace throughout the codebase.
>
> Would it be terribly difficult to make objects with ArrayAccess completel=
y
> interchangable anywhere an array element would be required by a function?

Yes, definitely, it would be a quite big amount of work (basically
rewriting every functions dealing with arrays), and the interface that
ArrayAccess proposes isn't enough for most array tasks.

>



--=20
Etienne Kneuss
http://www.colder.ch