rt-lists 0.1.2

Link lib
Documentation 
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use std::mem;

type Link = Option<Box<Node>>;

#[allow(dead_code)]
struct Node {
  elem: i32,
  next: Link,
}

pub struct List {
  head: Link,
}

impl List {
  pub fn new() -> Self {
    List { head: None }
  }

  pub fn push(&mut self, elem: i32) {
    let new_node = Box::new(Node {
      elem: elem,
      next: self.head.take(),
    });
    self.head = Some(new_node);
  }

  pub fn pop(&mut self) -> Option<i32> {
    match mem::replace(&mut self.head, None) {
      None => None,
      Some(node) => {
        self.head = node.next;
        Some(node.elem)
      }
    }
  }

  pub fn peek(&self) -> Option<i32> {
    match &self.head {
      None => None,
      Some(node) => {
        Some(node.elem)
      }
    }
  }
}

impl Drop for List {
  fn drop(&mut self) {
    let mut cur_link = self.head.take();
    while let Some(mut boxed_node) = cur_link {
      cur_link = boxed_node.next.take();
    }
  }
}