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use {
crate::{Symbol, Value},
std::collections::HashMap,
};
pub struct OMap {
map: HashMap<Symbol, Value>,
order: Vec<Symbol>,
}
impl OMap {
pub fn new() -> OMap {
OMap {
map: HashMap::new(),
order: Vec::new(),
}
}
pub fn len(&self) -> usize {
debug_assert!(self.map.len() == self.order.len());
self.map.len()
}
pub fn get<S: Into<Symbol>>(&self, key: S) -> Option<&Value> {
self.map.get(&key.into())
}
pub fn insert<S: Into<Symbol>>(&mut self, key: S, val: Value) {
debug_assert!(self.map.len() == self.order.len());
let sym = key.into();
self.map.insert(sym.clone(), val);
self.order.push(sym);
}
pub fn remove<S: Into<Symbol>>(&mut self, key: S) {
debug_assert!(self.map.len() == self.order.len());
let sym = key.into();
self.map.remove(&sym);
self.order
.remove(self.order.iter().position(|s| s == &sym).unwrap());
}
pub fn iter(&self) -> impl Iterator<Item = (&Symbol, &Value)> {
self.order
.iter()
.map(move |k| (k, self.map.get(k).unwrap()))
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_insert() {
let mut map = OMap::new();
map.insert("name", "Cyndi L.".into());
assert_eq!("Cyndi L.", map.get(&Symbol::from("name")).unwrap().to_str());
map.remove("name");
assert_eq!(None, map.get(&Symbol::from("name")));
}
#[test]
fn test_iter() {
let mut map = OMap::new();
map.insert("name", "Bilbo Baggins".into());
map.insert("age", "111".into());
let mut out = String::new();
for (k, v) in map.iter() {
out.push_str(&format!("{}: {}\n", k, v));
}
assert_eq!("name: Bilbo Baggins\nage: 111\n", out);
}
}