/// ```
/// #![feature(map_entry_replace)]
/// use std::collections::hash_map::{Entry, HashMap};
+ /// use std::rc::Rc;
///
- /// let mut map: HashMap<String, u32> = HashMap::new();
- /// map.insert("poneyland".to_string(), 15);
+ /// let mut map: HashMap<Rc<String>, u32> = HashMap::new();
+ /// map.insert(Rc::new("Stringthing".to_string()), 15);
///
- /// if let Entry::Occupied(entry) = map.entry("poneyland".to_string()) {
- /// let (old_key, old_value): (String, u32) = entry.replace_entry(16);
- /// assert_eq!(old_key, "poneyland");
- /// assert_eq!(old_value, 15);
+ /// let my_key = Rc::new("Stringthing".to_string());
+ ///
+ /// if let Entry::Occupied(entry) = map.entry(my_key) {
+ /// // Also replace the key with a handle to our other key.
+ /// let (old_key, old_value): (Rc<String>, u32) = entry.replace_entry(16);
/// }
///
- /// assert_eq!(map.get("poneyland"), Some(&16));
/// ```
#[unstable(feature = "map_entry_replace", issue = "44286")]
pub fn replace_entry(mut self, value: V) -> (K, V) {
/// ```
/// #![feature(map_entry_replace)]
/// use std::collections::hash_map::{Entry, HashMap};
+ /// use std::rc::Rc;
+ ///
+ /// let mut map: HashMap<Rc<String>, u32> = HashMap::new();
+ /// let mut known_strings: Vec<Rc<String>> = Vec::new();
+ ///
+ /// // Initialise known strings, run program, etc.
///
- /// let mut map: HashMap<String, u32> = HashMap::new();
- /// map.insert("poneyland".to_string(), 15);
+ /// reclaim_memory(&mut map, &known_strings);
///
- /// if let Entry::Occupied(entry) = map.entry("poneyland".to_string()) {
- /// let old_key = entry.replace_key();
- /// assert_eq!(old_key, "poneyland");
+ /// fn reclaim_memory(map: &mut HashMap<Rc<String>, u32>, known_strings: &[Rc<String>] ) {
+ /// for s in known_strings {
+ /// if let Entry::Occupied(entry) = map.entry(s.clone()) {
+ /// // Replaces the entry's key with our version of it in `known_strings`.
+ /// entry.replace_key();
+ /// }
+ /// }
/// }
/// ```
#[unstable(feature = "map_entry_replace", issue = "44286")]