/**
* Filter the WFArray according to function $fn. If calling $fn($item)
* returns true, include the item in the result, otherwise exclude it.
*
* @param WFFunction A WFFunction that returns true to include the item and false to exclude it.
* @return WFArray The filtered array.
*/
public function filter(WFFunction $fn)
{
$filtered = new WFArray();
foreach ($this as $entry) {
$include = $fn->call($entry);
if ($include) {
$filtered->append($entry);
}
}
return $filtered;
}