PresetAbstract::flatten

static function flatten(array $someArray): array
{
	$plainStructure = [];
	$flatten = function($value, $key, $parent) use (&$plainStructure, &$flatten) {
		if (is_string($key))
		{
			$plainStructure[$key] = $parent;
			$parent = $key;
		}
		if (is_array($value))
		{
			array_walk($value, $flatten, $parent);
		}
		else
		{
			$plainStructure[strval($value)] = $parent;
		}
	};

	array_walk($someArray, $flatten, null);
	return $plainStructure;
}