use crate::List::{Cons, Nil}; | |
use std::cell::RefCell; | |
use std::rc::Rc; | |
#[derive(Debug)] | |
enum List { | |
Cons(i32, RefCell<Rc<List>>), | |
Nil, | |
} | |
impl List { | |
fn tail(&self) -> Option<&RefCell<Rc<List>>> { | |
match self { | |
Cons(_, item) => Some(item), | |
Nil => None, | |
} | |
} | |
} | |
fn main() {} |