Struct regex_syntax::CharClass

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:

1. Given any Unicode scalar value, it is matched by at most one character range in a canonical character class.
2. Every adjacent character range is separated by at least one Unicode scalar value.
3. Given any pair of character ranges r1 and r2, if r1.end < r2.start, then r1 comes before r2 in 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:

1. Simple case folding has been applied to all ranges.
2. 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 to be len elements long, 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, 5];
vec.truncate(2);
assert_eq!(vec, [1, 2]);

fn as_slice(&self) -> &[T]

Extracts a slice containing the entire vector.

Equivalent to &s[..].

fn as_mut_slice(&mut self) -> &mut [T]

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 it 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 it 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>

Create a draining iterator that removes the specified range in the vector and yields the removed items.

Note 1: The element range is removed even if the iterator is not consumed until the end.

Note 2: 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

let mut v = vec![1, 2, 3];
let u: Vec<_> = v.drain(1..).collect();
assert_eq!(v, &[1]);
assert_eq!(u, &[2, 3]);

// A full range clears the vector
v.drain(..);
assert_eq!(v, &[]);

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.

If new_len is greater than len(), the Vec is extended by the difference, with each additional slot filled with value. If new_len is less than len(), the Vec is simply truncated.

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])

Deprecated since 1.6.0

: renamed to extend_from_slice

fn extend_from_slice(&mut self, other: &[T])

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.

Note that this function is same as extend except that it is specialized to work with slices instead. If and when Rust gets specialization this function will likely be deprecated (but still available).

Examples

let mut vec = vec![1];
vec.extend_from_slice(&[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]);

Trait Implementations

impl Deref for CharClass

type Target = Vec<ClassRange>

fn deref(&self) -> &Vec<ClassRange>

impl IntoIterator for CharClass

type Item = ClassRange

type IntoIter = IntoIter<ClassRange>

fn into_iter(self) -> IntoIter<ClassRange>

impl<'a> IntoIterator for &'a CharClass

type Item = &'a ClassRange

type IntoIter = Iter<'a, ClassRange>

fn into_iter(self) -> Iter<'a, ClassRange>

impl Display for CharClass

fn fmt(&self, f: &mut Formatter) -> Result

Derived Implementations

impl Eq for CharClass

impl PartialEq for CharClass

fn eq(&self, __arg_0: &CharClass) -> bool

fn ne(&self, __arg_0: &CharClass) -> bool

impl Debug for CharClass

fn fmt(&self, __arg_0: &mut Formatter) -> Result

impl Clone for CharClass

fn clone(&self) -> CharClass

fn clone_from(&mut self, source: &Self)