iterator_ext/
try_scan.rs

1use crate::common::*;
2
3#[derive(Debug)]
4pub struct TryScan<I, St, F> {
5    pub(super) iter: Option<I>,
6    pub(super) state: St,
7    pub(super) f: F,
8}
9
10impl<I, St, F, T, U, E> Iterator for TryScan<I, St, F>
11where
12    I: Iterator<Item = Result<T, E>>,
13    F: FnMut(&mut St, T) -> Result<Option<U>, E>,
14{
15    type Item = Result<U, E>;
16
17    fn next(&mut self) -> Option<Self::Item> {
18        let mut iter = match self.iter.take() {
19            Some(iter) => iter,
20            None => return None,
21        };
22
23        let input_item = match iter.next() {
24            Some(Ok(item)) => item,
25            Some(Err(err)) => {
26                return Some(Err(err));
27            }
28            None => {
29                return None;
30            }
31        };
32
33        let output_item = match (self.f)(&mut self.state, input_item) {
34            Ok(Some(item)) => item,
35            Ok(None) => return None,
36            Err(err) => return Some(Err(err)),
37        };
38
39        self.iter = Some(iter);
40        Some(Ok(output_item))
41    }
42}
iterator_ext/try_scan.rs

iterator_ext/
try_scan.rs
