orx_iterable/transformations/
taken.rs

1use crate::{Collection, CollectionMut, Iterable};
2use core::marker::PhantomData;
3use orx_self_or::SoM;
4
5/// Wraps an `Iterable` and creates a new `Iterable` which yields only the first `n` the elements
6/// of the original iterable.
7pub struct Taken<I>
8where
9    I: Iterable,
10{
11    pub(crate) it: I,
12    pub(crate) n: usize,
13}
14
15impl<I> Iterable for Taken<I>
16where
17    I: Iterable,
18{
19    type Item = I::Item;
20
21    type Iter = core::iter::Take<I::Iter>;
22
23    fn iter(&self) -> Self::Iter {
24        self.it.iter().take(self.n)
25    }
26}
27
28// col
29
30/// Wraps an `Collection` and creates a new `Collection` which yields only the first `n` the elements
31/// of the original iterable.
32pub struct TakenCol<I, E>
33where
34    I: Collection,
35    E: SoM<I>,
36{
37    pub(crate) it: E,
38    pub(crate) n: usize,
39    pub(crate) phantom: PhantomData<I>,
40}
41
42impl<'a, I, E> Iterable for &'a TakenCol<I, E>
43where
44    I: Collection,
45    E: SoM<I>,
46{
47    type Item = &'a I::Item;
48
49    type Iter = core::iter::Take<<I::Iterable<'a> as Iterable>::Iter>;
50
51    fn iter(&self) -> Self::Iter {
52        self.it.get_ref().iter().take(self.n)
53    }
54}
55
56impl<I, E> Collection for TakenCol<I, E>
57where
58    I: Collection,
59    E: SoM<I>,
60{
61    type Item = I::Item;
62
63    type Iterable<'i> = &'i Self
64    where
65        Self: 'i;
66
67    fn as_iterable(&self) -> Self::Iterable<'_> {
68        self
69    }
70}
71
72impl<I, E> CollectionMut for TakenCol<I, E>
73where
74    I: CollectionMut,
75    E: SoM<I>,
76{
77    type IterMut<'i> = core::iter::Take<I::IterMut<'i>>
78    where
79        Self: 'i;
80
81    fn iter_mut(&mut self) -> Self::IterMut<'_> {
82        self.it.get_mut().iter_mut().take(self.n)
83    }
84}
orx_iterable/transformations/taken.rs

orx_iterable/transformations/
taken.rs
