Struct regex_syntax::CharClass
[−]
[src]
pub struct CharClass {
// some fields omitted
}A character class.
A character class has a canonical format that the parser guarantees. Its canonical format is defined by the following invariants:
- Given any Unicode scalar value, it is matched by at most one character range in a canonical character class.
- Every adjacent character range is separated by at least one Unicode scalar value.
- Given any pair of character ranges
r1andr2, ifr1.end < r2.start, thenr1comes beforer2in a canonical character class.
In sum, any CharClass produced by this crate's parser is a sorted
sequence of non-overlapping ranges. This makes it possible to test whether
a character is matched by a class with a binary search.
Additionally, a character class may be marked case insensitive. If it's case insensitive, then:
- Simple case folding has been applied to all ranges.
- Simple case folding must be applied to a character before testing whether it matches the character class.
Methods
impl CharClass
fn new(ranges: Vec<ClassRange>) -> CharClass
Create a new class from an existing set of ranges.
fn matches(&self, c: char) -> bool
Returns true if c is matched by this character class.
fn negate(self) -> CharClass
Negates the character class.
For all c where c is a Unicode scalar value, c matches self
if and only if c does not match self.negate().
fn case_fold(self) -> CharClass
Apply case folding to this character class.
N.B. Applying case folding to a negated character class probably
won't produce the expected result. e.g., (?i)[^x] really should
match any character sans x and X, but if [^x] is negated
before being case folded, you'll end up matching any character.
Methods from Deref<Target=Vec<ClassRange>>
fn capacity(&self) -> usize
Returns the number of elements the vector can hold without reallocating.
Examples
let vec: Vec<i32> = Vec::with_capacity(10); assert_eq!(vec.capacity(), 10);
fn reserve(&mut self, additional: usize)
Reserves capacity for at least additional more elements to be inserted
in the given Vec<T>. The collection may reserve more space to avoid
frequent reallocations.
Panics
Panics if the new capacity overflows usize.
Examples
let mut vec = vec![1]; vec.reserve(10); assert!(vec.capacity() >= 11);
fn reserve_exact(&mut self, additional: usize)
Reserves the minimum capacity for exactly additional more elements to
be inserted in the given Vec<T>. Does nothing if the capacity is already
sufficient.
Note that the allocator may give the collection more space than it
requests. Therefore capacity can not be relied upon to be precisely
minimal. Prefer reserve if future insertions are expected.
Panics
Panics if the new capacity overflows usize.
Examples
let mut vec = vec![1]; vec.reserve_exact(10); assert!(vec.capacity() >= 11);
fn shrink_to_fit(&mut self)
Shrinks the capacity of the vector as much as possible.
It will drop down as close as possible to the length but the allocator may still inform the vector that there is space for a few more elements.
Examples
let mut vec = Vec::with_capacity(10); vec.extend([1, 2, 3].iter().cloned()); assert_eq!(vec.capacity(), 10); vec.shrink_to_fit(); assert!(vec.capacity() >= 3);
fn into_boxed_slice(self) -> Box<[T]>
Converts the vector into Box<[T]>.
Note that this will drop any excess capacity. Calling this and
converting back to a vector with into_vec() is equivalent to calling
shrink_to_fit().
fn truncate(&mut self, len: usize)
Shorten a vector, dropping excess elements.
If len is greater than the vector's current length, this has no
effect.
Examples
let mut vec = vec![1, 2, 3, 4]; vec.truncate(2); assert_eq!(vec, [1, 2]);
fn as_slice(&self) -> &[T]
convert): waiting on RFC revision
Extracts a slice containing the entire vector.
Equivalent to &s[..].
fn as_mut_slice(&mut self) -> &mut [T]
convert): waiting on RFC revision
Extracts a mutable slice of the entire vector.
Equivalent to &mut s[..].
unsafe fn set_len(&mut self, len: usize)
Sets the length of a vector.
This will explicitly set the size of the vector, without actually modifying its buffers, so it is up to the caller to ensure that the vector is actually the specified size.
Examples
let mut v = vec![1, 2, 3, 4]; unsafe { v.set_len(1); }
fn swap_remove(&mut self, index: usize) -> T
Removes an element from anywhere in the vector and return it, replacing it with the last element.
This does not preserve ordering, but is O(1).
Panics
Panics if index is out of bounds.
Examples
let mut v = vec!["foo", "bar", "baz", "qux"]; assert_eq!(v.swap_remove(1), "bar"); assert_eq!(v, ["foo", "qux", "baz"]); assert_eq!(v.swap_remove(0), "foo"); assert_eq!(v, ["baz", "qux"]);
fn insert(&mut self, index: usize, element: T)
Inserts an element at position index within the vector, shifting all
elements after position i one position to the right.
Panics
Panics if index is greater than the vector's length.
Examples
let mut vec = vec![1, 2, 3]; vec.insert(1, 4); assert_eq!(vec, [1, 4, 2, 3]); vec.insert(4, 5); assert_eq!(vec, [1, 4, 2, 3, 5]);
fn remove(&mut self, index: usize) -> T
Removes and returns the element at position index within the vector,
shifting all elements after position index one position to the left.
Panics
Panics if index is out of bounds.
Examples
let mut v = vec![1, 2, 3]; assert_eq!(v.remove(1), 2); assert_eq!(v, [1, 3]);
fn retain<F>(&mut self, f: F) where 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.
This method operates in place and preserves the order of the retained
elements.
Examples
let mut vec = vec![1, 2, 3, 4]; vec.retain(|&x| x%2 == 0); assert_eq!(vec, [2, 4]);
fn push(&mut self, value: T)
Appends an element to the back of a collection.
Panics
Panics if the number of elements in the vector overflows a usize.
Examples
let mut vec = vec![1, 2]; vec.push(3); assert_eq!(vec, [1, 2, 3]);
fn pop(&mut self) -> Option<T>
Removes the last element from a vector and returns it, or None if it
is empty.
Examples
let mut vec = vec![1, 2, 3]; assert_eq!(vec.pop(), Some(3)); assert_eq!(vec, [1, 2]);
fn append(&mut self, other: &mut Vec<T>)
Moves all the elements of other into Self, leaving other empty.
Panics
Panics if the number of elements in the vector overflows a usize.
Examples
let mut vec = vec![1, 2, 3]; let mut vec2 = vec![4, 5, 6]; vec.append(&mut vec2); assert_eq!(vec, [1, 2, 3, 4, 5, 6]); assert_eq!(vec2, []);
fn drain<R>(&mut self, range: R) -> Drain<T> where R: RangeArgument<usize>
drain): recently added, matches RFC
Create a draining iterator that removes the specified range in the vector and yields the removed items from start to end. The element range is removed even if the iterator is not consumed until the end.
Note: It is unspecified how many elements are removed from the vector,
if the Drain value is leaked.
Panics
Panics if the starting point is greater than the end point or if the end point is greater than the length of the vector.
Examples
#![feature(drain)] // Draining using `..` clears the whole vector. let mut v = vec![1, 2, 3]; let u: Vec<_> = v.drain(..).collect(); assert_eq!(v, &[]); assert_eq!(u, &[1, 2, 3]);
fn clear(&mut self)
Clears the vector, removing all values.
Examples
let mut v = vec![1, 2, 3]; v.clear(); assert!(v.is_empty());
fn len(&self) -> usize
Returns the number of elements in the vector.
Examples
let a = vec![1, 2, 3]; assert_eq!(a.len(), 3);
fn is_empty(&self) -> bool
Returns true if the vector contains no elements.
Examples
let mut v = Vec::new(); assert!(v.is_empty()); v.push(1); assert!(!v.is_empty());
fn split_off(&mut self, at: usize) -> Vec<T>
Splits the collection into two at the given index.
Returns a newly allocated Self. self contains elements [0, at),
and the returned Self contains elements [at, len).
Note that the capacity of self does not change.
Panics
Panics if at > len.
Examples
let mut vec = vec![1,2,3]; let vec2 = vec.split_off(1); assert_eq!(vec, [1]); assert_eq!(vec2, [2, 3]);
fn resize(&mut self, new_len: usize, value: T)
Resizes the Vec in-place so that len() is equal to new_len.
Calls either extend() or truncate() depending on whether new_len
is larger than the current value of len() or not.
Examples
let mut vec = vec!["hello"]; vec.resize(3, "world"); assert_eq!(vec, ["hello", "world", "world"]); let mut vec = vec![1, 2, 3, 4]; vec.resize(2, 0); assert_eq!(vec, [1, 2]);
fn push_all(&mut self, other: &[T])
vec_push_all): likely to be replaced by a more optimized extend
Appends all elements in a slice to the Vec.
Iterates over the slice other, clones each element, and then appends
it to this Vec. The other vector is traversed in-order.
Examples
#![feature(vec_push_all)] let mut vec = vec![1]; vec.push_all(&[2, 3, 4]); assert_eq!(vec, [1, 2, 3, 4]);
fn dedup(&mut self)
Removes consecutive repeated elements in the vector.
If the vector is sorted, this removes all duplicates.
Examples
let mut vec = vec![1, 2, 2, 3, 2]; vec.dedup(); assert_eq!(vec, [1, 2, 3, 2]);