Struct slab::VacantEntry

pub struct VacantEntry<'a, T> {
    pub(crate) slab: &'a mut Slab<T>,
    pub(crate) key: usize,
}

A handle to a vacant entry in a Slab.

VacantEntry allows constructing values with the key that they will be assigned to.

Examples

let mut slab = Slab::new();

let hello = {
    let entry = slab.vacant_entry();
    let key = entry.key();

    entry.insert((key, "hello"));
    key
};

assert_eq!(hello, slab[hello].0);
assert_eq!("hello", slab[hello].1);

Fields

slab: &'a mut Slab<T>

key: usize

Implementations

impl<'a, T> VacantEntry<'a, T>

pub fn insert(self, val: T) -> &'a mut T

Insert a value in the entry, returning a mutable reference to the value.

To get the key associated with the value, use key prior to calling insert.

Examples

let mut slab = Slab::new();

let hello = {
    let entry = slab.vacant_entry();
    let key = entry.key();

    entry.insert((key, "hello"));
    key
};

assert_eq!(hello, slab[hello].0);
assert_eq!("hello", slab[hello].1);

pub fn key(&self) -> usize

Return the key associated with this entry.

A value stored in this entry will be associated with this key.

Examples

let mut slab = Slab::new();

let hello = {
    let entry = slab.vacant_entry();
    let key = entry.key();

    entry.insert((key, "hello"));
    key
};

assert_eq!(hello, slab[hello].0);
assert_eq!("hello", slab[hello].1);

Trait Implementations

impl<'a, T: Debug> Debug for VacantEntry<'a, T>

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

Formats the value using the given formatter.