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
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
//! Extension for [`std::result::Result`].
/// Extension methods for [`std::result::Result`].
pub trait ResultExt<T, E> {
/// Tap into a `Result` and modify its `Ok` value.
///
/// This method captures the `Result` in order not to break the caller-chain.
///
/// ## Example
///
/// ```rust
/// use rs_std_ext::result::ResultExt;
///
/// let mut x: Result<String, usize> = Ok("4".into());
/// assert_eq!(x.tap_mut(|s| s.push('2')), Ok("42".into()));
/// ```
fn tap_mut(self, f: impl FnOnce(&mut T)) -> Result<T, E>;
/// Tap into a `Result` and modify its `Err` value.
///
/// This method captures the `Result` in order not to break the caller-chain.
///
/// ## Example
///
/// ```rust
/// use rs_std_ext::result::ResultExt;
///
/// let mut x: Result<String, usize> = Err(40);
/// assert_eq!(x.tap_err_mut(|s| *s += 2), Err(42));
/// ```
fn tap_err_mut(self, f: impl FnOnce(&mut E)) -> Result<T, E>;
/// Swap the `Ok` and `Err` values of a `Result`.
///
/// ## Example
///
/// ```rust
/// use rs_std_ext::result::ResultExt;
///
/// let x: Result<&str, usize> = Ok("foo");
/// assert_eq!(x.swap(), Err("foo"));
/// ```
fn swap(self) -> Result<E, T>;
}
impl<T, E> ResultExt<T, E> for Result<T, E> {
fn tap_mut(mut self, f: impl FnOnce(&mut T)) -> Result<T, E> {
if let Ok(val) = &mut self {
f(val)
}
self
}
fn tap_err_mut(mut self, f: impl FnOnce(&mut E)) -> Result<T, E> {
if let Err(e) = &mut self {
f(e)
}
self
}
fn swap(self) -> Result<E, T> {
match self {
Ok(t) => Err(t),
Err(e) => Ok(e),
}
}
}