/// Pops and returns the value at the front of the list.
Pops and returns the value at the front of the list.
Pops and returns the value at the front of the list .
fn pop_front(&mut self) -> T {
        let node = self.arena.remove(self.head).unwrap();
        self.link(NULL, node.next);
        self.head = node.next;
        if node.next == NULL {
            self.tail = NULL;
        }
        node.value
    }
fn pop_front ( & mut self ) -> T { let node = self . arena . remove ( self . head ) . unwrap ( ) ; self . link ( NULL , node . next ) ; self . head = node . next ; if node . next == NULL { self . tail = NULL ; } node . value }
Pops and returns the value at the front of the list.
Pops and returns the value at the front of the list .
&mut self