Enum slotmap::secondary::Entry

pub enum Entry<'a, K: Key, V> {
    Occupied(OccupiedEntry<'a, K, V>),
    Vacant(VacantEntry<'a, K, V>),
}

A view into a single entry in a SecondaryMap, which may either be vacant or occupied.

This enum is constructed using SecondaryMap::entry.

Variants

Occupied(OccupiedEntry<'a, K, V>)

An occupied entry.

Vacant(VacantEntry<'a, K, V>)

A vacant entry.

Implementations

impl<'a, K: Key, V> Entry<'a, K, V>

pub fn or_insert(self, default: V) -> &'a mut V

Ensures a value is in the entry by inserting the default if empty, and returns a mutable reference to the value in the entry.

Examples

let mut sm = SlotMap::new();
let mut sec = SecondaryMap::new();

let k = sm.insert("poneyland");
let v = sec.entry(k).unwrap().or_insert(10);
assert_eq!(*v, 10);
*sec.entry(k).unwrap().or_insert(1) *= 2;
assert_eq!(sec[k], 20);

pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V

Ensures a value is in the entry by inserting the result of the default function if empty, and returns a mutable reference to the value in the entry.

Examples

let mut sm = SlotMap::new();
let mut sec = SecondaryMap::new();

let k = sm.insert(1);
let v = sec.entry(k).unwrap().or_insert_with(|| "foobar".to_string());
assert_eq!(v, &"foobar");

pub fn key(&self) -> K

Returns this entry’s key.

Examples

let mut sm = SlotMap::new();
let mut sec: SecondaryMap<_, ()> = SecondaryMap::new();

let k = sm.insert(1);
let entry = sec.entry(k).unwrap();
assert_eq!(entry.key(), k);

pub fn and_modify<F>(self, f: F) -> Self

where F: FnOnce(&mut V),

Provides in-place mutable access to an occupied entry before any potential inserts into the map.

Examples

let mut sm = SlotMap::new();
let mut sec = SecondaryMap::new();

let k = sm.insert(1);
sec.insert(k, 0);
sec.entry(k).unwrap().and_modify(|x| *x = 1);

assert_eq!(sec[k], 1)

impl<'a, K: Key, V: Default> Entry<'a, K, V>

pub fn or_default(self) -> &'a mut V

Ensures a value is in the entry by inserting the default value if empty, and returns a mutable reference to the value in the entry.

Examples

let mut sm = SlotMap::new();
let mut sec: SecondaryMap<_, Option<i32>> = SecondaryMap::new();

let k = sm.insert(1);
sec.entry(k).unwrap().or_default();
assert_eq!(sec[k], None)

Trait Implementations

impl<'a, K: Debug + Key, V: Debug> Debug for Entry<'a, K, V>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.