Struct edn::intern_set::InternSet
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pub struct InternSet<T> where
T: Eq + Hash, { /* fields omitted */ }
An InternSet
allows to "intern" some potentially large values, maintaining a single value
instance owned by the InternSet
and leaving consumers with lightweight ref-counted handles to
the large owned value. This can avoid expensive clone() operations.
In Mentat, such large values might be strings or arbitrary [a v] pairs.
See https://en.wikipedia.org/wiki/String_interning for discussion.
Methods
impl<T> InternSet<T> where
T: Eq + Hash,
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T: Eq + Hash,
pub fn new() -> InternSet<T>
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pub fn intern<R: Into<ValueRc<T>>>(&mut self, value: R) -> ValueRc<T>
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Intern a value, providing a ref-counted handle to the interned value.
use edn::{InternSet, ValueRc}; let mut s = InternSet::new(); let one = "foo".to_string(); let two = ValueRc::new("foo".to_string()); let out_one = s.intern(one); assert_eq!(out_one, two); // assert!(!&out_one.ptr_eq(&two)); // Nightly-only. let out_two = s.intern(two); assert_eq!(out_one, out_two); assert_eq!(1, s.len()); // assert!(&out_one.ptr_eq(&out_two)); // Nightly-only.
Methods from Deref<Target = HashSet<ValueRc<T>>>
ⓘImportant traits for &'a mut Rpub fn hasher(&self) -> &S
1.9.0[src]
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();
pub fn capacity(&self) -> usize
1.0.0[src]
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);
pub fn reserve(&mut self, additional: usize)
1.0.0[src]
Reserves capacity for at least additional
more elements to be inserted
in the HashSet
. The collection may reserve more space to avoid
frequent reallocations.
Panics
Panics if the new allocation size overflows usize
.
Examples
use std::collections::HashSet; let mut set: HashSet<i32> = HashSet::new(); set.reserve(10); assert!(set.capacity() >= 10);
pub fn shrink_to_fit(&mut self)
1.0.0[src]
Shrinks the capacity of the set as much as possible. It will drop down as much as possible while maintaining the internal rules and possibly leaving some space in accordance with the resize policy.
Examples
use std::collections::HashSet; let mut set = HashSet::with_capacity(100); set.insert(1); set.insert(2); assert!(set.capacity() >= 100); set.shrink_to_fit(); assert!(set.capacity() >= 2);
ⓘImportant traits for Iter<'a, K>pub fn iter(&self) -> Iter<T>
1.0.0[src]
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); }
ⓘImportant traits for Difference<'a, T, S>pub fn difference(&'a self, other: &'a HashSet<T, S>) -> Difference<'a, T, S>
1.0.0[src]
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<_> = [1, 2, 3].iter().cloned().collect(); let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); // 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());
ⓘImportant traits for SymmetricDifference<'a, T, S>pub fn symmetric_difference(
&'a self,
other: &'a HashSet<T, S>
) -> SymmetricDifference<'a, T, S>
1.0.0[src]
&'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<_> = [1, 2, 3].iter().cloned().collect(); let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); // 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());
ⓘImportant traits for Intersection<'a, T, S>pub fn intersection(
&'a self,
other: &'a HashSet<T, S>
) -> Intersection<'a, T, S>
1.0.0[src]
&'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
.
Examples
use std::collections::HashSet; let a: HashSet<_> = [1, 2, 3].iter().cloned().collect(); let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); // 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());
ⓘImportant traits for Union<'a, T, S>pub fn union(&'a self, other: &'a HashSet<T, S>) -> Union<'a, T, S>
1.0.0[src]
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<_> = [1, 2, 3].iter().cloned().collect(); let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); // 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());
pub fn len(&self) -> usize
1.0.0[src]
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);
pub fn is_empty(&self) -> bool
1.0.0[src]
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());
ⓘImportant traits for Drain<'a, K>pub fn drain(&mut self) -> Drain<T>
1.6.0[src]
Clears the set, returning all elements in an iterator.
Examples
use std::collections::HashSet; let mut set: HashSet<_> = [1, 2, 3].iter().cloned().collect(); assert!(!set.is_empty()); // print 1, 2, 3 in an arbitrary order for i in set.drain() { println!("{}", i); } assert!(set.is_empty());
pub fn clear(&mut self)
1.0.0[src]
Clears the set, removing all values.
Examples
use std::collections::HashSet; let mut v = HashSet::new(); v.insert(1); v.clear(); assert!(v.is_empty());
pub fn contains<Q>(&self, value: &Q) -> bool where
Q: Hash + Eq + ?Sized,
T: Borrow<Q>,
1.0.0[src]
Q: Hash + Eq + ?Sized,
T: Borrow<Q>,
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<_> = [1, 2, 3].iter().cloned().collect(); assert_eq!(set.contains(&1), true); assert_eq!(set.contains(&4), false);
pub fn get<Q>(&self, value: &Q) -> Option<&T> where
Q: Hash + Eq + ?Sized,
T: Borrow<Q>,
1.9.0[src]
Q: Hash + Eq + ?Sized,
T: Borrow<Q>,
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<_> = [1, 2, 3].iter().cloned().collect(); assert_eq!(set.get(&2), Some(&2)); assert_eq!(set.get(&4), None);
pub fn is_disjoint(&self, other: &HashSet<T, S>) -> bool
1.0.0[src]
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<_> = [1, 2, 3].iter().cloned().collect(); 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);
pub fn is_subset(&self, other: &HashSet<T, S>) -> bool
1.0.0[src]
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<_> = [1, 2, 3].iter().cloned().collect(); 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);
pub fn is_superset(&self, other: &HashSet<T, S>) -> bool
1.0.0[src]
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<_> = [1, 2].iter().cloned().collect(); 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);
pub fn insert(&mut self, value: T) -> bool
1.0.0[src]
Adds a value to the set.
If the set did not have this value present, true
is returned.
If the set did have this value present, false
is returned.
Examples
use std::collections::HashSet; let mut set = HashSet::new(); assert_eq!(set.insert(2), true); assert_eq!(set.insert(2), false); assert_eq!(set.len(), 1);
pub fn replace(&mut self, value: T) -> Option<T>
1.9.0[src]
Adds a value to the set, replacing the existing value, if any, that is equal to the given one. Returns the replaced value.
Examples
use std::collections::HashSet; let mut set = HashSet::new(); set.insert(Vec::<i32>::new()); assert_eq!(set.get(&[][..]).unwrap().capacity(), 0); set.replace(Vec::with_capacity(10)); assert_eq!(set.get(&[][..]).unwrap().capacity(), 10);
pub fn remove<Q>(&mut self, value: &Q) -> bool where
Q: Hash + Eq + ?Sized,
T: Borrow<Q>,
1.0.0[src]
Q: Hash + Eq + ?Sized,
T: Borrow<Q>,
Removes a value from the set. Returns true
if the value was
present in the set.
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 mut set = HashSet::new(); set.insert(2); assert_eq!(set.remove(&2), true); assert_eq!(set.remove(&2), false);
pub fn take<Q>(&mut self, value: &Q) -> Option<T> where
Q: Hash + Eq + ?Sized,
T: Borrow<Q>,
1.9.0[src]
Q: Hash + Eq + ?Sized,
T: Borrow<Q>,
Removes and returns the value in the set, if any, that is equal to the given one.
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 mut set: HashSet<_> = [1, 2, 3].iter().cloned().collect(); assert_eq!(set.take(&2), Some(2)); assert_eq!(set.take(&2), None);
pub fn retain<F>(&mut self, f: F) where
F: FnMut(&T) -> bool,
1.18.0[src]
F: FnMut(&T) -> bool,
Retains only the elements specified by the predicate.
In other words, remove all elements e
such that f(&e)
returns false
.
Examples
use std::collections::HashSet; let xs = [1,2,3,4,5,6]; let mut set: HashSet<isize> = xs.iter().cloned().collect(); set.retain(|&k| k % 2 == 0); assert_eq!(set.len(), 3);
Trait Implementations
impl<T: Clone> Clone for InternSet<T> where
T: Eq + Hash,
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T: Eq + Hash,
fn clone(&self) -> InternSet<T>
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Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
1.0.0[src]
Performs copy-assignment from source
. Read more
impl<T: Debug> Debug for InternSet<T> where
T: Eq + Hash,
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T: Eq + Hash,
fn fmt(&self, __arg_0: &mut Formatter) -> Result
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Formats the value using the given formatter. Read more
impl<T: Default> Default for InternSet<T> where
T: Eq + Hash,
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T: Eq + Hash,
impl<T: Eq> Eq for InternSet<T> where
T: Eq + Hash,
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T: Eq + Hash,
impl<T: PartialEq> PartialEq for InternSet<T> where
T: Eq + Hash,
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T: Eq + Hash,
fn eq(&self, __arg_0: &InternSet<T>) -> bool
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This method tests for self
and other
values to be equal, and is used by ==
. Read more
fn ne(&self, __arg_0: &InternSet<T>) -> bool
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This method tests for !=
.
impl<T> Deref for InternSet<T> where
T: Eq + Hash,
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T: Eq + Hash,
type Target = HashSet<ValueRc<T>>
The resulting type after dereferencing.
fn deref(&self) -> &Self::Target
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Dereferences the value.
impl<T> DerefMut for InternSet<T> where
T: Eq + Hash,
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T: Eq + Hash,