peace_diff/
equality.rs

1use std::{cmp::Ordering, fmt};
2
3/// Represents whether a value is equal to another.
4#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
5pub enum Equality {
6    /// Values are not equal.
7    NotEqual,
8    /// Values are equal.
9    Equal,
10    /// Cannot determine equality of values.
11    ///
12    /// This is when either or both [`Tracked`] values are [`Tracked::Unknown`].
13    ///
14    /// [`Tracked`]: crate::Tracked
15    /// [`Tracked::Unknown`]: crate::Tracked::Unknown
16    Unknown,
17}
18
19impl fmt::Display for Equality {
20    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
21        match self {
22            Self::NotEqual => "!=".fmt(f),
23            Self::Equal => "==".fmt(f),
24            Self::Unknown => "?=".fmt(f),
25        }
26    }
27}
28
29impl PartialOrd for Equality {
30    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
31        // Currently using this order:
32        //
33        // ```
34        // NotEqual < Equal < Unknown
35        // ```
36        match (self, other) {
37            (Self::NotEqual, Self::NotEqual) => Some(Ordering::Equal),
38            (Self::NotEqual, Self::Equal) => Some(Ordering::Less),
39            (Self::NotEqual, Self::Unknown) => Some(Ordering::Less),
40            (Self::Equal, Self::NotEqual) => Some(Ordering::Greater),
41            (Self::Equal, Self::Equal) => Some(Ordering::Equal),
42            (Self::Equal, Self::Unknown) => Some(Ordering::Less),
43            (Self::Unknown, Self::NotEqual) => Some(Ordering::Greater),
44            (Self::Unknown, Self::Equal) => Some(Ordering::Greater),
45            (Self::Unknown, Self::Unknown) => None,
46        }
47    }
48}
49
50impl From<bool> for Equality {
51    fn from(eq: bool) -> Self {
52        if eq {
53            Equality::Equal
54        } else {
55            Equality::NotEqual
56        }
57    }
58}
59
60impl From<Equality> for bool {
61    fn from(equality: Equality) -> bool {
62        match equality {
63            Equality::NotEqual => false,
64            Equality::Equal => true,
65            Equality::Unknown => false,
66        }
67    }
68}
peace_diff/equality.rs

peace_diff/
equality.rs
