rust_query/
mymap.rs

1use std::ops::{Deref, DerefMut};
2
3#[derive(Clone)]
4pub struct MyMap<K, V> {
5    inner: Vec<(K, V)>,
6}
7
8impl<K: PartialEq, V> MyMap<K, V> {
9    pub fn pos_or_init(&mut self, k: K, f: impl FnOnce() -> V) -> usize {
10        if let Some(res) = self.inner.iter().position(|x| x.0 == k) {
11            return res;
12        }
13        let len = self.inner.len();
14        self.inner.push((k, f()));
15        len
16    }
17
18    pub fn get_or_init(&mut self, k: K, f: impl FnOnce() -> V) -> &V {
19        let idx = self.pos_or_init(k, f);
20        &self.inner[idx].1
21    }
22
23    pub fn into_iter(self) -> std::vec::IntoIter<(K, V)> {
24        self.inner.into_iter()
25    }
26}
27
28impl<K, V> Default for MyMap<K, V> {
29    fn default() -> Self {
30        Self {
31            inner: Default::default(),
32        }
33    }
34}
35
36impl<K, V> Deref for MyMap<K, V> {
37    type Target = Vec<(K, V)>;
38
39    fn deref(&self) -> &Self::Target {
40        &self.inner
41    }
42}
43
44impl<K, V> DerefMut for MyMap<K, V> {
45    fn deref_mut(&mut self) -> &mut Self::Target {
46        &mut self.inner
47    }
48}
rust_query/mymap.rs

rust_query/
mymap.rs
