Method or_insert_with

src/entity/sparse.rs:394–402

(self, call: F)

    where
        F: FnOnce() -> V,
    {
        match self {
            Entry::Occupied(entry) => entry.into_mut(),
            Entry::Vacant(entry) => entry.insert(call()),
        }
    }

    /// Inserts the result of the `call` function with a reference to the entry's key if it is
    /// vacant, and returns a mutable reference to the new value. Otherwise a mutable reference to
    /// an already existent value is returned.
    #[inline]
    pub fn or_insert_with_key<F>(self, call: F) -> &'a mut V