diffus/diffable_impls/
option.rs

1use crate::{
2    edit::{self, enm},
3    Diffable,
4};
5
6impl<'a, T: Diffable<'a> + 'a> Diffable<'a> for Option<T> {
7    type Diff = enm::Edit<'a, Self, T::Diff>;
8
9    fn diff(&'a self, other: &'a Self) -> edit::Edit<Self> {
10        match (self, other) {
11            (None, None) => edit::Edit::Copy(self),
12            (Some(a), Some(b)) => match a.diff(&b) {
13                edit::Edit::Copy(_) => edit::Edit::Copy(self),
14                edit::Edit::Change(diff) => edit::Edit::Change(enm::Edit::AssociatedChanged(diff)),
15            },
16            _ => edit::Edit::Change(enm::Edit::VariantChanged(self, other)),
17        }
18    }
19}
20
21#[cfg(test)]
22mod tests {
23    use super::*;
24
25    #[test]
26    fn is_copy() {
27        assert!((None as Option<u32>).diff(&None).is_copy());
28        assert!(Some(3).diff(&Some(3)).is_copy());
29    }
30
31    #[test]
32    fn variant_changed() {
33        if let Some(enm::Edit::VariantChanged(&None, &Some(3))) = None.diff(&Some(3)).change() {
34        } else {
35            unreachable!();
36        }
37    }
38
39    #[test]
40    fn associate_change() {
41        if let Some(enm::Edit::AssociatedChanged((&1, &2))) = Some(1).diff(&Some(2)).change() {
42        } else {
43            unreachable!();
44        }
45    }
46}
diffus/diffable_impls/option.rs

diffus/diffable_impls/
option.rs
