forked from RustPython/RustPython
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathfold_helpers.rs
More file actions
72 lines (66 loc) · 1.57 KB
/
fold_helpers.rs
File metadata and controls
72 lines (66 loc) · 1.57 KB
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
70
71
72
use crate::constant;
use crate::fold::Fold;
pub(crate) trait Foldable<T, U> {
type Mapped;
fn fold<F: Fold<T, TargetU = U> + ?Sized>(
self,
folder: &mut F,
) -> Result<Self::Mapped, F::Error>;
}
impl<T, U, X> Foldable<T, U> for Vec<X>
where
X: Foldable<T, U>,
{
type Mapped = Vec<X::Mapped>;
fn fold<F: Fold<T, TargetU = U> + ?Sized>(
self,
folder: &mut F,
) -> Result<Self::Mapped, F::Error> {
self.into_iter().map(|x| x.fold(folder)).collect()
}
}
impl<T, U, X> Foldable<T, U> for Option<X>
where
X: Foldable<T, U>,
{
type Mapped = Option<X::Mapped>;
fn fold<F: Fold<T, TargetU = U> + ?Sized>(
self,
folder: &mut F,
) -> Result<Self::Mapped, F::Error> {
self.map(|x| x.fold(folder)).transpose()
}
}
impl<T, U, X> Foldable<T, U> for Box<X>
where
X: Foldable<T, U>,
{
type Mapped = Box<X::Mapped>;
fn fold<F: Fold<T, TargetU = U> + ?Sized>(
self,
folder: &mut F,
) -> Result<Self::Mapped, F::Error> {
(*self).fold(folder).map(Box::new)
}
}
macro_rules! simple_fold {
($($t:ty),+$(,)?) => {
$(impl<T, U> $crate::fold_helpers::Foldable<T, U> for $t {
type Mapped = Self;
#[inline]
fn fold<F: Fold<T, TargetU = U> + ?Sized>(
self,
_folder: &mut F,
) -> Result<Self::Mapped, F::Error> {
Ok(self)
}
})+
};
}
simple_fold!(
usize,
String,
bool,
constant::Constant,
constant::ConversionFlag
);