src/doc/book/listings/ch15-smart-pointers/listing-15-25/src/main.rs

   1 use crate::List::{Cons, Nil};
   2 use std::cell::RefCell;
   3 use std::rc::Rc;
   4
   5 #[derive(Debug)]
   6 enum List {
   7     Cons(i32, RefCell<Rc<List>>),
   8     Nil,
   9 }
  10
  11 impl List {
  12     fn tail(&self) -> Option<&RefCell<Rc<List>>> {
  13         match self {
  14             Cons(_, item) => Some(item),
  15             Nil => None,
  16         }
  17     }
  18 }
  19
  20 fn main() {}