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Date: Sun, 30 Oct 2016 12:24:43 +0100
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To: Nikita Popov <nikita.ppv@gmail.com>
Cc: Levi Morrison <levim@php.net>, David Lundgren <dlundgren@syberisle.net>, 
	internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Allow Iterator to be used with current, next, reset,
 key functions
From: rasmus@mindplay.dk (Rasmus Schultz)

With regards to deprecating array-functions that operate on the
internal pointer - I'd like to just remind you of the fact that some
of these functions, reset() and end() in particular, are often used
not because someone cares about moving the internal pointer, but as a
means of getting the first/last items of an array.

If the internal pointers are removed, I'd like to suggest we improve
the reset() and end() functions rather than removing them - there is
an annoyance with these two functions presently: because they operate
on the internal pointer, the force you to introduce often meaningless
intermediary variables.

That is, for example:

    $last = end(explode(",", $comma_separated_values));

Doesn't work. One is forced to introduce a variable:

    $parts = explode(",", $comma_separated_values);
    $last = end($parts);

If internal pointers are removed, maybe the reset() and end()
functions could be made to actually work consistently? Whether applied
to an expression or variable.



On Sat, Oct 29, 2016 at 10:06 PM, Nikita Popov <nikita.ppv@gmail.com> wrote:
> On Fri, Oct 28, 2016 at 2:43 PM, Levi Morrison <levim@php.net> wrote:
>
>> On Wed, Oct 26, 2016 at 7:42 AM, David Lundgren <dlundgren@syberisle.net>
>> wrote:
>> > Greetings,
>> >
>> > As suggested by several reviewers of a PR[1] I recently submitted, I'd
>> > like to get feedback on letting custom Iterators be used in the current,
>> > next, reset, and key functions. If this is something to move forward
>> > with, I'll need some help with the RFC process.
>> >
>> > Recent experiences trying to use these functions with a custom Iterator,
>> > and a bug[2], led me to try and fix this. BC will occur when an object
>> > implementing Iterator is passed to one of the functions, as the
>> > interface methods will be called, instead of returning the objects
>> > properties. The old behavior should be maintained for classes that do
>> > not implement Iterator.
>> >
>> > [1] https://github.com/php/php-src/pull/2176
>> > [2] https://bugs.php.net/bug.php?id=49369
>> >
>> > Thanks,
>> > Dave
>> > --
>> > David Lundgren
>> > dlundgren@syberisle.net
>> > 808.639.0365
>> > GPG: 0x26F54D7F
>> >
>> > --
>> > PHP Internals - PHP Runtime Development Mailing List
>> > To unsubscribe, visit: http://www.php.net/unsub.php
>>
>> I can't seem to recall specifics anymore but I do believe some people
>> would greatly prefer to remove the internal array pointer for
>> iteration and deprecate these functions. Maybe someone else can
>> remember more? Nikita and Bob, maybe?
>>
>
> Yeah, I'm one of those people. In PHP 7 the most important user of the IAP,
> foreach, was switched to use a more robust mechanism. I believe that at
> this point, the concept of an internal array pointer has outlived its
> usefulness and we should be working toward removing any APIs that publicly
> expose it, including each and the next/current/key family of functions. I
> will propose to deprecate each() in particular for PHP 7.2, because it is
> both more problematic and more useless than the others, but I'd like to see
> the others go away in the long term as well. If people want fine-grained
> control over array iteration, they should use an external iterator (aka
> ArrayIterator), not an internal one.
>
> Nikita