iterator_endiate/
lib.rs

1#![doc = include_str!("../README.md")]
2
3/// Extension trait for adding [EndiateIteratorExt::endiate] and [EndiateIteratorExt::nendiate]
4pub trait EndiateIteratorExt: Sized {
5    /// Similar to [`Iterator::enumerate`] but rather including indexes, it includes whether the item
6    /// is the last item in the iterator
7    /// ```
8    /// use iterator_endiate::EndiateIteratorExt;
9    /// let endiate = [1, 2, 3].into_iter().endiate().collect::<Vec<_>>();
10    /// assert_eq!(
11    ///     endiate,
12    ///     [
13    ///         (false, 1),
14    ///         (false, 2),
15    ///         (true, 3),
16    ///     ]
17    /// )
18    /// ```
19    fn endiate(self) -> Endiate<Self>;
20
21    /// Same as [EndiateIteratorExt::endiate] but bool is **not** at end
22    /// ```
23    /// use iterator_endiate::EndiateIteratorExt;
24    /// let nendiate = [1, 2, 3].into_iter().nendiate().collect::<Vec<_>>();
25    /// assert_eq!(
26    ///     nendiate,
27    ///     [
28    ///         (true, 1),
29    ///         (true, 2),
30    ///         (false, 3),
31    ///     ]
32    /// )
33    /// ```
34    fn nendiate(self) -> NEndiate<Self>;
35}
36
37impl<Iter: ExactSizeIterator> EndiateIteratorExt for Iter {
38    fn endiate(self) -> Endiate<Self> {
39        Endiate(self)
40    }
41
42    fn nendiate(self) -> NEndiate<Self> {
43        NEndiate(Endiate(self))
44    }
45}
46
47/// From [EndiateIteratorExt::endiate]
48pub struct Endiate<Iter>(pub(crate) Iter);
49
50/// From [EndiateIteratorExt::nendiate]
51pub struct NEndiate<Iter>(pub(crate) Endiate<Iter>);
52
53impl<Iter: ExactSizeIterator> Iterator for Endiate<Iter> {
54    type Item = (bool, Iter::Item);
55
56    fn next(&mut self) -> Option<Self::Item> {
57        self.0.next().map(|v| (self.0.len() == 0, v))
58    }
59}
60
61impl<Iter: ExactSizeIterator> Iterator for NEndiate<Iter> {
62    type Item = (bool, Iter::Item);
63
64    fn next(&mut self) -> Option<Self::Item> {
65        self.0.next().map(|(at_end, v)| (!at_end, v))
66    }
67}
68
69impl<Iter: ExactSizeIterator> ExactSizeIterator for Endiate<Iter> {}
70
71impl<Iter: ExactSizeIterator> ExactSizeIterator for NEndiate<Iter> {}
iterator_endiate/lib.rs

iterator_endiate/
lib.rs
