FlatMap implementation in PHP, following the Reactive Extensions intiative

flatMap.php

function flatMap($data, \Closure $p)
{
    $collection = call_user_func_array("array_map", array($p));

    return iterator_to_array(new \RecursiveIteratorIterator(
         new \RecursiveArrayIterator($data)), false);
}

Example:

$data = [0, 1, 2, 3, 4, 5];
$fatenData = flatMap($data, function($x) {
return [$x, $x + 1];
});
// [0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6]

See: https://github.com/LellysInformatica/collections

what is $collection doing?
https://gist.github.com/italolelis/2712c6c671b50864748b#file-flatmap-php-L3

How could you deal with nested elements?

$col = new MyCollection(1, 2, 3, new MyCollection(4, 5, 6), 7, 8, new MyCollection(9));

To obtain:

$res = $col->flatMap(function($x) {
    return array($x, $x+1);
});

$res ===> [1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10]