50 lines
1.2 KiB
Rust
50 lines
1.2 KiB
Rust
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use std::{
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borrow::Borrow,
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cmp::Eq,
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collections::{HashMap, HashSet},
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hash::Hash,
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};
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pub trait Contains<'a, T: Eq + Hash> {
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type Item: Borrow<T>;
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type Iter: Iterator<Item = Self::Item>;
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fn contains(&self, key: &T) -> bool;
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fn contains_iter(&'a self) -> Self::Iter;
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}
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impl<'a, T: 'a + Eq + Hash, U: 'a> Contains<'a, T> for HashMap<T, U> {
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type Item = &'a T;
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type Iter = std::collections::hash_map::Keys<'a, T, U>;
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fn contains(&self, key: &T) -> bool {
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<HashMap<T, U>>::contains_key(self, key)
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}
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fn contains_iter(&'a self) -> Self::Iter {
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self.keys()
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}
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}
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impl<'a, T: 'a + Eq + Hash> Contains<'a, T> for HashSet<T> {
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type Item = &'a T;
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type Iter = std::collections::hash_set::Iter<'a, T>;
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fn contains(&self, key: &T) -> bool {
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<HashSet<T>>::contains(self, key)
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}
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fn contains_iter(&'a self) -> Self::Iter {
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self.iter()
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}
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}
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impl<'a, T: 'a + Eq + Hash + Copy> Contains<'a, T> for T {
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type Item = &'a T;
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type Iter = std::iter::Once<&'a T>;
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fn contains(&self, key: &T) -> bool {
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key == self
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}
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fn contains_iter(&'a self) -> Self::Iter {
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std::iter::once(self)
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}
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}
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