ArrayIterator improvements for PHP's (linked) hash tables

• Version: 1.0
• Date: 2016-11-21
• Author: @WesNetmo on Twitter - with Room 11's help
• Status: Draft
• First Published at: https://wiki.php.net/rfc/arrayiterator-improvements

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

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

After calling this method, `ArrayIterator::current()` would return the value associated with the specified `$key`, `ArrayIterator::key()` will return `$key` and so on. If the `$key` doesn't exist the method would return `false` and Iterator would keep its current state, otherwise the method would return `true`.

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

This method would simply move the Iterator's cursor to the previous Entry in the hash table's linked list. Exactly like `next()` it would never throw and it would always return `null`, but if there is no previous Entry, after calling it, an immediate call to the `valid()` method would return `false`.

None, for both of the proposed methods.

PHP 7.2

Accept `ArrayIterator::seekKey($key)`? Requires a 50% + 1 majority.

*votes*

Accept `ArrayIterator::prev()`? Requires a 50% + 1 majority.

*votes*

N/A