====== ArrayIterator improvements ======

  * Version: 2.0
  * Date: 2016-11-21
  * Author: @WesNetmo on Twitter - with Room 11's help
  * Status: Under Discussion
  * First Published at: https://wiki.php.net/rfc/arrayiterator-improvements

===== Proposal =====

This RFC proposes the addition of a couple of functions that would expose to userland important features of PHP's (linked) hash-tables.

===== ArrayIterator::seekKey($key):void (throws OutOfBoundsException) =====

This method would move the Iterator's cursor to the Entry identified by the key ''$key''.

The existing method ''ArrayIterator::seek($position)'' searches for the Entry in a linear manner, and this is not ideal for many uses, as what it does is simply iterating over the array (or part of it) to reach the specified position (or key, assuming the array is a list). Instead, the proposed method ''ArrayIterator::seekKey($key)'' would be a ''O(1)'' operation as the cursor can immediately jump to the Entry identified by the given ''$key''.

Specifically, if the given key is present in the array the method would successfully execute such that subsequent calls to ''ArrayIterator::current()'' would get the value associated with the specified ''$key'', ''ArrayIterator::key()'' would get ''$key'' and so on, like it would normally behave when iterating over the Entry. Instead, if the provided key is not present in the array, and exactly like ''ArrayIterator::seek($position)'', the method would throw a ''OutOfBoundsException'' and keep the current ''ArrayIterator'''s cursor state.

===== ArrayIterator::prev():void =====

This method would simply move the Iterator's cursor to the previous Entry in the hash table's linked list. Exactly like ''ArrayIterator::next()'', it would never throw and it would always return ''null''. However, if there is no previous Entry, immediate calls to the ''valid()'' method would return ''false''.




===== Backward Incompatible Changes =====

None, for both of the proposed methods.

===== Proposed PHP Version(s) =====

PHP 7.2

===== Proposed Voting Choices =====

Accept ArrayIterator::seekKey($key) for PHP 7.2?

* vote 1 *

Accept ArrayIterator::prev() for PHP 7.2?

* vote 2 *

===== Patches and Tests =====

None yet.

===== References =====
[[http://externals.io/thread/510|Discussion thread]]