#![allow(dead_code)]
use std::{borrow::Borrow, collections::HashMap, hash::Hash};
#[derive(Clone, Debug)]
pub struct TrainMap<'a, K, V> {
pub map: HashMap<K, V>,
pub parent: Option<&'a TrainMap<'a, K, V>>,
}
impl<'a, K: Eq + Hash, V> TrainMap<'a, K, V> {
pub fn new() -> Self {
Self {
map: Default::default(),
parent: None,
}
}
pub fn with_capacity(capacity: usize) -> Self {
Self {
map: HashMap::with_capacity(capacity),
parent: None,
}
}
pub fn keys(&self) -> Vec<&K> {
let mut keys = self.map.keys().collect::<Vec<_>>();
if let Some(parent) = self.parent {
keys.extend(parent.keys().into_iter().collect::<Vec<_>>())
}
keys
}
pub fn get<Q: Eq + Hash + ?Sized>(&self, key: &Q) -> Option<&V>
where
K: Borrow<Q>,
{
if let Some(value) = self.map.get(key) {
Some(value)
} else if let Some(parent) = self.parent {
parent.get(key)
} else {
None
}
}
pub fn insert(&mut self, key: K, value: V) -> Option<V> {
self.map.insert(key, value)
}
pub fn fork(&'a self) -> Self {
Self {
map: Default::default(),
parent: Some(self),
}
}
}
impl<'a, K: Eq + Hash, V> Default for TrainMap<'a, K, V> {
fn default() -> Self {
Self::new()
}
}
impl<'a, K: Eq + Hash, V> Extend<(K, V)> for TrainMap<'a, K, V> {
fn extend<T: IntoIterator<Item = (K, V)>>(&mut self, iterator: T) {
self.map.extend(iterator)
}
}