trie_rs/iter/
keys.rs

1#[derive(Debug, Clone)]
2/// Retains keys and strips off `Value`s from a [crate::iter] iterator.
3pub struct Keys<I>(I);
4
5impl<I> Keys<I> {
6    ///Creates a new `Keys` iterator.
7    pub fn new(iter: I) -> Self {
8        Self(iter)
9    }
10}
11
12// TODO: This is generic for V, which is a stand-in for the Value, but in a
13// `map::Trie<K,V>`, its iterators will actually reurn `(C, &V)`. Hopefully that
14// won't matter.
15impl<I, C, V> Iterator for Keys<I>
16where
17    I: Iterator<Item = (C, V)>,
18{
19    type Item = C;
20    fn next(&mut self) -> Option<C> {
21        self.0.next().map(|x| x.0)
22    }
23}
24
25/// Strip an iterator items `(K, V)` to only have `K`.
26pub trait KeysExt: Iterator {
27    /// Retain keys and strip values from a [crate::iter] iterator.
28    fn keys(self) -> Keys<Self>
29    where
30        Self: Sized,
31    {
32        Keys::new(self)
33    }
34}
35
36impl<T> KeysExt for T where T: Iterator + ?Sized {}
trie_rs/iter/keys.rs

trie_rs/iter/
keys.rs
