public function fmap(\Closure $trans) {
        return $this->flightcontrol()->newFDirectory($this, function() use ($trans) { 
            return array_map($trans, $this->fcontents());
        });
    }
public function fmap(\Closure $trans) {
        return $this->flightcontrol()->newFDirectory($this, function() use ($trans) { 
            return array_map($trans, $this->fcontents());
        });
    }
public function fmap ( \ Closure $ trans ) { return $ this -> flightcontrol ( ) -> newFDirectory ( $ this , function ( ) use ( $ trans ) { return array_map ( $ trans , $ this -> fcontents ( ) ) ; } ) ; }
As this is as functor, we could map over it.

Turns an FDirectory a to an FDirectory b by using the provided $trans
function.

@param   \Closure    $trans   a -> b
@return  FDirectory
As this is as functor we could map over it .