Struct regex_syntax::CharClass

pub struct CharClass { /* 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.

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].

Implementations

impl CharClass

pub fn new(ranges: Vec<ClassRange>) -> CharClass

Create a new class from an existing set of ranges.

pub fn matches(&self, c: char) -> bool

Returns true if c is matched by this character class.

pub fn remove(&mut self, c: char)

Removes the given character from the class if it exists.

Note that this takes O(n) time in the number of ranges.

pub 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().

pub 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>>

pub 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);

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

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();

pub fn as_ptr(&self) -> *const T

Returns a raw pointer to the vector’s buffer.

The caller must ensure that the vector outlives the pointer this function returns, or else it will end up pointing to garbage. Modifying the vector may cause its buffer to be reallocated, which would also make any pointers to it invalid.

The caller must also ensure that the memory the pointer (non-transitively) points to is never written to (except inside an UnsafeCell) using this pointer or any pointer derived from it. If you need to mutate the contents of the slice, use as_mut_ptr.

Examples

let x = vec![1, 2, 4];
let x_ptr = x.as_ptr();

unsafe {
    for i in 0..x.len() {
        assert_eq!(*x_ptr.add(i), 1 << i);
    }
}

pub fn allocator(&self) -> &A

🔬 This is a nightly-only experimental API. (allocator_api)

Returns a reference to the underlying allocator.

pub fn len(&self) -> usize

Returns the number of elements in the vector, also referred to as its ‘length’.

Examples

let a = vec![1, 2, 3];
assert_eq!(a.len(), 3);

pub 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());

Trait Implementations

impl Clone for CharClass

fn clone(&self) -> CharClass

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for CharClass

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

Formats the value using the given formatter.

impl Deref for CharClass

type Target = Vec<ClassRange>

The resulting type after dereferencing.

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

Dereferences the value.

impl Display for CharClass

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

Formats the value using the given formatter.

impl IntoIterator for CharClass

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.

impl<'a> IntoIterator for &'a CharClass

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.

impl PartialEq<CharClass> for CharClass

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl Eq for CharClass

impl StructuralEq for CharClass

impl StructuralPartialEq for CharClass