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
r1
andr2
, ifr1.end < r2.start
, thenr1
comes beforer2
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.
If the case insensitive flag was set when parsing a character class, then
simple case folding is done automatically. For example, (?i)[a-c]
is
automatically translated to [a-cA-C]
.
Methods
impl CharClass
[src]
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
1.0.0
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)
1.0.0
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)
1.0.0
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)
1.0.0
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]>
1.0.0
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()
.
Examples
let v = vec![1, 2, 3]; let slice = v.into_boxed_slice();
Any excess capacity is removed:
let mut vec = Vec::with_capacity(10); vec.extend([1, 2, 3].iter().cloned()); assert_eq!(vec.capacity(), 10); let slice = vec.into_boxed_slice(); assert_eq!(slice.into_vec().capacity(), 3);
fn truncate(&mut self, len: usize)
1.0.0
Shortens the vector, keeping the first len
elements and dropping
the rest.
If len
is greater than the vector's current length, this has no
effect.
The drain
method can emulate truncate
, but causes the excess
elements to be returned instead of dropped.
Examples
Truncating a five element vector to two elements:
let mut vec = vec![1, 2, 3, 4, 5]; vec.truncate(2); assert_eq!(vec, [1, 2]);
No truncation occurs when len
is greater than the vector's current
length:
let mut vec = vec![1, 2, 3]; vec.truncate(8); assert_eq!(vec, [1, 2, 3]);
Truncating when len == 0
is equivalent to calling the clear
method.
let mut vec = vec![1, 2, 3]; vec.truncate(0); assert_eq!(vec, []);
fn as_slice(&self) -> &[T]
1.7.0
Extracts a slice containing the entire vector.
Equivalent to &s[..]
.
Examples
use std::io::{self, Write}; let buffer = vec![1, 2, 3, 5, 8]; io::sink().write(buffer.as_slice()).unwrap();
fn as_mut_slice(&mut self) -> &mut [T]
1.7.0
Extracts a mutable slice of the entire vector.
Equivalent to &mut s[..]
.
Examples
use std::io::{self, Read}; let mut buffer = vec![0; 3]; io::repeat(0b101).read_exact(buffer.as_mut_slice()).unwrap();
unsafe fn set_len(&mut self, len: usize)
1.0.0
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
use std::ptr; let mut vec = vec!['r', 'u', 's', 't']; unsafe { ptr::drop_in_place(&mut vec[3]); vec.set_len(3); } assert_eq!(vec, ['r', 'u', 's']);
In this example, there is a memory leak since the memory locations
owned by the inner vectors were not freed prior to the set_len
call:
let mut vec = vec![vec![1, 0, 0], vec![0, 1, 0], vec![0, 0, 1]]; unsafe { vec.set_len(0); }
In this example, the vector gets expanded from zero to four items without any memory allocations occurring, resulting in vector values of unallocated memory:
let mut vec: Vec<char> = Vec::new(); unsafe { vec.set_len(4); }
fn swap_remove(&mut self, index: usize) -> T
1.0.0
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)
1.0.0
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
1.0.0
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
1.0.0
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)
1.0.0
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>
1.0.0
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>)
1.4.0
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>
1.6.0
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)
1.0.0
Clears the vector, removing all values.
Examples
let mut v = vec![1, 2, 3]; v.clear(); assert!(v.is_empty());
fn len(&self) -> usize
1.0.0
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
1.0.0
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>
1.4.0
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)
1.5.0
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 extend_from_slice(&mut self, other: &[T])
1.6.0
Clones and 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)
1.0.0
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 Eq for CharClass
[src]
impl PartialEq for CharClass
[src]
fn eq(&self, __arg_0: &CharClass) -> bool
This method tests for self
and other
values to be equal, and is used by ==
. Read more
fn ne(&self, __arg_0: &CharClass) -> bool
This method tests for !=
.
impl Debug for CharClass
[src]
impl Clone for CharClass
[src]
fn clone(&self) -> CharClass
Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
1.0.0
Performs copy-assignment from source
. Read more
impl Deref for CharClass
[src]
type Target = Vec<ClassRange>
The resulting type after dereferencing
fn deref(&self) -> &Vec<ClassRange>
The method called to dereference a value
impl IntoIterator for CharClass
[src]
type Item = ClassRange
The type of the elements being iterated over.
type IntoIter = IntoIter<ClassRange>
Which kind of iterator are we turning this into?
fn into_iter(self) -> IntoIter<ClassRange>
Creates an iterator from a value. Read more
impl<'a> IntoIterator for &'a CharClass
[src]
type Item = &'a ClassRange
The type of the elements being iterated over.
type IntoIter = Iter<'a, ClassRange>
Which kind of iterator are we turning this into?
fn into_iter(self) -> Iter<'a, ClassRange>
Creates an iterator from a value. Read more