1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
use crate::Profile;
use crate::value::{Value, Map};
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum Order {
Merge,
Join
}
pub trait Coalescible: Sized {
fn coalesce(self, other: Self, order: Order) -> Self;
fn merge(self, other: Self) -> Self { self.coalesce(other, Order::Merge) }
}
impl Coalescible for Profile {
fn coalesce(self, other: Self, order: Order) -> Self {
if order == Order::Join { self } else { other }
}
}
impl Coalescible for Value {
fn coalesce(self, other: Self, order: Order) -> Self {
use {Value::Dict as D, Order::Join as L, Order::Merge as R};
match (self, other, order) {
(D(t, a), D(_, b), L) | (D(_, a), D(t, b), R) => D(t, a.coalesce(b, order)),
(v, _, L) | (_, v, R) => v,
}
}
}
impl<K: Eq + std::hash::Hash + Ord, V: Coalescible> Coalescible for Map<K, V> {
fn coalesce(self, mut other: Self, order: Order) -> Self {
let mut joined = Map::new();
for (a_key, a_val) in self {
match other.remove(&a_key) {
Some(b_val) => joined.insert(a_key, a_val.coalesce(b_val, order)),
None => joined.insert(a_key, a_val),
};
}
joined.extend(other);
joined
}
}