• Version: 1.0
• Date: 2022-06-21
• Author: Tim Düsterhus, duesterhus@woltlab.com
• Status: Draft
• First Published at: http://wiki.php.net/rfc/iterator_xyz_accept_array

PHP's iterator_*() family currently only accept \Traversables (i.e. they reject plain arrays). This is unnecessarily limiting.

Specifically this concerns the iterator_to_array(), iterator_count() functions. While each of them has an array-specific counterpart, the fact that one needs to choose either the array-specific variant or the everything-but-array variant makes writing code the deals with arbitrary iterables unnecessarily verbose.

Specifically allowing iterator_to_array() to take an array, makes it much easier to write functions accepting an iterable and processing it using array_map() et al:

function before(iterable $foo) {
    if (!is_array($foo)) {
        $foo = iterator_to_array($foo);
    }
 
    return array_map(strlen(...), $foo);
}
function after(iterable $foo) {
    $foo = iterator_to_array($foo);
 
    return array_map(strlen(...), $foo);
}

The $iterator parameter of iterator_to_array() and iterator_count() should be widened from \Traversable to iterable (i.e. to \Traversable|array).

Specifically if this RFC is accepted the following shall hold:

iterator_to_array($array, true) == $array
iterator_to_array($array, false) == array_values($array)

iterator_count($array) == count($array)

This function is not part of this proposal, because it is non-obvious how to define the behavior for arrays, given that it does not pass the Iterator to the callback by default.

None, this is a purely type widening change.

next PHP 8.x

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Anything that isn't iterator_to_array() or iterator_count().

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Each vote requires a 2/3 majority..

• Vote 1: Change the type of iterator_to_array()'s $iterator parameter from \Traversable to iterable?
• Vote 2: Change the type of iterator_count()'s $iterator parameter from \Traversable to iterable?

PoC implementation to iterator_to_array: https://github.com/php/php-src/pull/8819

n/a

• Pre-RFC discussion: https://externals.io/message/117979
• PoC implementation: https://github.com/php/php-src/pull/8819
• Similar previous RFC that proposed adding new functions with an iterable_* prefix: https://wiki.php.net/rfc/iterable_to_array-and-iterable_count
• Stack Overflow asking for iterable_to_array(): https://stackoverflow.com/q/44587973/782822

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