Struct just_a_tag::TagUnion
source · pub struct TagUnion(_);
Expand description
A tag union, e.g. foo
or foo+bar+baz
(i.e. foo
and bar
and baz
).
use just_a_tag::{Tag, TagUnion};
let union = TagUnion::from_str("foo").unwrap();
assert!(union.contains(&Tag::new("foo")));
assert_eq!(union.len(), 1);
let union = TagUnion::from_str("foo+bar").unwrap();
assert!(union.contains(&Tag::new("foo")));
assert!(union.contains(&Tag::new("bar")));
assert_eq!(union.len(), 2);
assert!(TagUnion::from_str("foo bar").is_err());
Implementations§
source§impl TagUnion
impl TagUnion
sourcepub fn matches_set(&self, values: &HashSet<Tag>) -> bool
pub fn matches_set(&self, values: &HashSet<Tag>) -> bool
Returns true
if this tag union matches the value presented in the set.
use std::collections::HashSet;
use just_a_tag::{MatchesAnyTagUnion, Tag, TagUnion};
let unions = vec![
TagUnion::from_str("foo").unwrap(),
TagUnion::from_str("bar+baz").unwrap()
];
// foo, and bar+baz matches
let set_1 = HashSet::from_iter([Tag::new("foo"), Tag::new("bar"), Tag::new("baz")]);
assert!(unions.matches_set(&set_1));
// bar+baz matches
let set_2 = HashSet::from_iter([Tag::new("fubar"), Tag::new("bar"), Tag::new("baz")]);
assert!(unions.matches_set(&set_2));
// foo matches
let set_3 = HashSet::from_iter([Tag::new("foo"), Tag::new("bar")]);
assert!(unions.matches_set(&set_3));
// none match
let set_4 = HashSet::from_iter([Tag::new("fubar"), Tag::new("bar")]);
assert!(!unions.matches_set(&set_4));
sourcepub fn insert(&mut self, tag: Tag) -> bool
pub fn insert(&mut self, tag: Tag) -> bool
Inserts a tag into this union. Returns whether the tag was inserted; that is:
- If the tag was not previously inserted,
true
is returned, - If the tag was previously inserted,
false
is returned.
sourcepub fn remove<T: Borrow<Tag>>(&mut self, tag: T) -> bool
pub fn remove<T: Borrow<Tag>>(&mut self, tag: T) -> bool
Removes a tag from this union. Returns whether the tag was removed; that is:
- If the tag was previously inserted,
true
is returned, - If the tag was not previously inserted,
false
is returned.
Methods from Deref<Target = HashSet<Tag>>§
1.0.0 · sourcepub fn capacity(&self) -> usize
pub fn capacity(&self) -> usize
Returns the number of elements the set can hold without reallocating.
Examples
use std::collections::HashSet;
let set: HashSet<i32> = HashSet::with_capacity(100);
assert!(set.capacity() >= 100);
1.0.0 · sourcepub fn iter(&self) -> Iter<'_, T>
pub fn iter(&self) -> Iter<'_, T>
An iterator visiting all elements in arbitrary order.
The iterator element type is &'a T
.
Examples
use std::collections::HashSet;
let mut set = HashSet::new();
set.insert("a");
set.insert("b");
// Will print in an arbitrary order.
for x in set.iter() {
println!("{x}");
}
Performance
In the current implementation, iterating over set takes O(capacity) time instead of O(len) because it internally visits empty buckets too.
1.0.0 · sourcepub fn len(&self) -> usize
pub fn len(&self) -> usize
Returns the number of elements in the set.
Examples
use std::collections::HashSet;
let mut v = HashSet::new();
assert_eq!(v.len(), 0);
v.insert(1);
assert_eq!(v.len(), 1);
1.0.0 · sourcepub fn is_empty(&self) -> bool
pub fn is_empty(&self) -> bool
Returns true
if the set contains no elements.
Examples
use std::collections::HashSet;
let mut v = HashSet::new();
assert!(v.is_empty());
v.insert(1);
assert!(!v.is_empty());
1.9.0 · sourcepub fn hasher(&self) -> &S
pub fn hasher(&self) -> &S
Returns a reference to the set’s BuildHasher
.
Examples
use std::collections::HashSet;
use std::collections::hash_map::RandomState;
let hasher = RandomState::new();
let set: HashSet<i32> = HashSet::with_hasher(hasher);
let hasher: &RandomState = set.hasher();
1.0.0 · sourcepub fn difference<'a>(
&'a self,
other: &'a HashSet<T, S>
) -> Difference<'a, T, S>
pub fn difference<'a>( &'a self, other: &'a HashSet<T, S> ) -> Difference<'a, T, S>
Visits the values representing the difference,
i.e., the values that are in self
but not in other
.
Examples
use std::collections::HashSet;
let a = HashSet::from([1, 2, 3]);
let b = HashSet::from([4, 2, 3, 4]);
// Can be seen as `a - b`.
for x in a.difference(&b) {
println!("{x}"); // Print 1
}
let diff: HashSet<_> = a.difference(&b).collect();
assert_eq!(diff, [1].iter().collect());
// Note that difference is not symmetric,
// and `b - a` means something else:
let diff: HashSet<_> = b.difference(&a).collect();
assert_eq!(diff, [4].iter().collect());
1.0.0 · sourcepub fn symmetric_difference<'a>(
&'a self,
other: &'a HashSet<T, S>
) -> SymmetricDifference<'a, T, S>
pub fn symmetric_difference<'a>( &'a self, other: &'a HashSet<T, S> ) -> SymmetricDifference<'a, T, S>
Visits the values representing the symmetric difference,
i.e., the values that are in self
or in other
but not in both.
Examples
use std::collections::HashSet;
let a = HashSet::from([1, 2, 3]);
let b = HashSet::from([4, 2, 3, 4]);
// Print 1, 4 in arbitrary order.
for x in a.symmetric_difference(&b) {
println!("{x}");
}
let diff1: HashSet<_> = a.symmetric_difference(&b).collect();
let diff2: HashSet<_> = b.symmetric_difference(&a).collect();
assert_eq!(diff1, diff2);
assert_eq!(diff1, [1, 4].iter().collect());
1.0.0 · sourcepub fn intersection<'a>(
&'a self,
other: &'a HashSet<T, S>
) -> Intersection<'a, T, S>
pub fn intersection<'a>( &'a self, other: &'a HashSet<T, S> ) -> Intersection<'a, T, S>
Visits the values representing the intersection,
i.e., the values that are both in self
and other
.
When an equal element is present in self
and other
then the resulting Intersection
may yield references to
one or the other. This can be relevant if T
contains fields which
are not compared by its Eq
implementation, and may hold different
value between the two equal copies of T
in the two sets.
Examples
use std::collections::HashSet;
let a = HashSet::from([1, 2, 3]);
let b = HashSet::from([4, 2, 3, 4]);
// Print 2, 3 in arbitrary order.
for x in a.intersection(&b) {
println!("{x}");
}
let intersection: HashSet<_> = a.intersection(&b).collect();
assert_eq!(intersection, [2, 3].iter().collect());
1.0.0 · sourcepub fn union<'a>(&'a self, other: &'a HashSet<T, S>) -> Union<'a, T, S>
pub fn union<'a>(&'a self, other: &'a HashSet<T, S>) -> Union<'a, T, S>
Visits the values representing the union,
i.e., all the values in self
or other
, without duplicates.
Examples
use std::collections::HashSet;
let a = HashSet::from([1, 2, 3]);
let b = HashSet::from([4, 2, 3, 4]);
// Print 1, 2, 3, 4 in arbitrary order.
for x in a.union(&b) {
println!("{x}");
}
let union: HashSet<_> = a.union(&b).collect();
assert_eq!(union, [1, 2, 3, 4].iter().collect());
1.0.0 · sourcepub fn contains<Q>(&self, value: &Q) -> boolwhere
T: Borrow<Q>,
Q: Hash + Eq + ?Sized,
pub fn contains<Q>(&self, value: &Q) -> boolwhere T: Borrow<Q>, Q: Hash + Eq + ?Sized,
Returns true
if the set contains a value.
The value may be any borrowed form of the set’s value type, but
Hash
and Eq
on the borrowed form must match those for
the value type.
Examples
use std::collections::HashSet;
let set = HashSet::from([1, 2, 3]);
assert_eq!(set.contains(&1), true);
assert_eq!(set.contains(&4), false);
1.9.0 · sourcepub fn get<Q>(&self, value: &Q) -> Option<&T>where
T: Borrow<Q>,
Q: Hash + Eq + ?Sized,
pub fn get<Q>(&self, value: &Q) -> Option<&T>where T: Borrow<Q>, Q: Hash + Eq + ?Sized,
Returns a reference to the value in the set, if any, that is equal to the given value.
The value may be any borrowed form of the set’s value type, but
Hash
and Eq
on the borrowed form must match those for
the value type.
Examples
use std::collections::HashSet;
let set = HashSet::from([1, 2, 3]);
assert_eq!(set.get(&2), Some(&2));
assert_eq!(set.get(&4), None);
1.0.0 · sourcepub fn is_disjoint(&self, other: &HashSet<T, S>) -> bool
pub fn is_disjoint(&self, other: &HashSet<T, S>) -> bool
Returns true
if self
has no elements in common with other
.
This is equivalent to checking for an empty intersection.
Examples
use std::collections::HashSet;
let a = HashSet::from([1, 2, 3]);
let mut b = HashSet::new();
assert_eq!(a.is_disjoint(&b), true);
b.insert(4);
assert_eq!(a.is_disjoint(&b), true);
b.insert(1);
assert_eq!(a.is_disjoint(&b), false);
1.0.0 · sourcepub fn is_subset(&self, other: &HashSet<T, S>) -> bool
pub fn is_subset(&self, other: &HashSet<T, S>) -> bool
Returns true
if the set is a subset of another,
i.e., other
contains at least all the values in self
.
Examples
use std::collections::HashSet;
let sup = HashSet::from([1, 2, 3]);
let mut set = HashSet::new();
assert_eq!(set.is_subset(&sup), true);
set.insert(2);
assert_eq!(set.is_subset(&sup), true);
set.insert(4);
assert_eq!(set.is_subset(&sup), false);
1.0.0 · sourcepub fn is_superset(&self, other: &HashSet<T, S>) -> bool
pub fn is_superset(&self, other: &HashSet<T, S>) -> bool
Returns true
if the set is a superset of another,
i.e., self
contains at least all the values in other
.
Examples
use std::collections::HashSet;
let sub = HashSet::from([1, 2]);
let mut set = HashSet::new();
assert_eq!(set.is_superset(&sub), false);
set.insert(0);
set.insert(1);
assert_eq!(set.is_superset(&sub), false);
set.insert(2);
assert_eq!(set.is_superset(&sub), true);
Trait Implementations§
source§impl<'de> Deserialize<'de> for TagUnion
Available on crate feature serde
only.
impl<'de> Deserialize<'de> for TagUnion
serde
only.