Struct regex_syntax::hir::literal::Literal
[−]
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pub struct Literal { /* fields omitted */ }
A single member of a set of literals extracted from a regular expression.
This type has Deref
and DerefMut
impls to Vec<u8>
so that all slice
and Vec
operations are available.
Methods
impl Literal
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pub fn new(bytes: Vec<u8>) -> Literal
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Returns a new complete literal with the bytes given.
pub fn empty() -> Literal
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Returns a new complete empty literal.
pub fn is_cut(&self) -> bool
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Returns true if this literal was "cut."
pub fn cut(&mut self)
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Cuts this literal.
Methods from Deref<Target = Vec<u8>>
pub fn capacity(&self) -> usize
1.0.0[src]
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 reserve(&mut self, additional: usize)
1.0.0[src]
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. After calling reserve
, capacity will be
greater than or equal to self.len() + additional
. Does nothing if
capacity is already sufficient.
Panics
Panics if the new capacity overflows usize
.
Examples
let mut vec = vec![1]; vec.reserve(10); assert!(vec.capacity() >= 11);
pub fn reserve_exact(&mut self, additional: usize)
1.0.0[src]
Reserves the minimum capacity for exactly additional
more elements to
be inserted in the given Vec<T>
. After calling reserve_exact
,
capacity will be greater than or equal to self.len() + additional
.
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);
pub fn try_reserve(
&mut self,
additional: usize
) -> Result<(), CollectionAllocErr>
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&mut self,
additional: usize
) -> Result<(), CollectionAllocErr>
🔬 This is a nightly-only experimental API. (try_reserve
)
new API
Tries to reserve 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. After calling reserve
, capacity will be
greater than or equal to self.len() + additional
. Does nothing if
capacity is already sufficient.
Errors
If the capacity overflows, or the allocator reports a failure, then an error is returned.
Examples
#![feature(try_reserve)] use std::collections::CollectionAllocErr; fn process_data(data: &[u32]) -> Result<Vec<u32>, CollectionAllocErr> { let mut output = Vec::new(); // Pre-reserve the memory, exiting if we can't output.try_reserve(data.len())?; // Now we know this can't OOM in the middle of our complex work output.extend(data.iter().map(|&val| { val * 2 + 5 // very complicated })); Ok(output) }
pub fn try_reserve_exact(
&mut self,
additional: usize
) -> Result<(), CollectionAllocErr>
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&mut self,
additional: usize
) -> Result<(), CollectionAllocErr>
🔬 This is a nightly-only experimental API. (try_reserve
)
new API
Tries to reserves the minimum capacity for exactly additional
more elements to
be inserted in the given Vec<T>
. After calling reserve_exact
,
capacity will be greater than or equal to self.len() + additional
.
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.
Errors
If the capacity overflows, or the allocator reports a failure, then an error is returned.
Examples
#![feature(try_reserve)] use std::collections::CollectionAllocErr; fn process_data(data: &[u32]) -> Result<Vec<u32>, CollectionAllocErr> { let mut output = Vec::new(); // Pre-reserve the memory, exiting if we can't output.try_reserve(data.len())?; // Now we know this can't OOM in the middle of our complex work output.extend(data.iter().map(|&val| { val * 2 + 5 // very complicated })); Ok(output) }
pub fn shrink_to_fit(&mut self)
1.0.0[src]
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);
pub fn truncate(&mut self, len: usize)
1.0.0[src]
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.
Note that this method has no effect on the allocated capacity of the vector.
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, []);
pub fn as_slice(&self) -> &[T]
1.7.0[src]
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_mut_slice(&mut self) -> &mut [T]
1.7.0[src]
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();
pub unsafe fn set_len(&mut self, len: usize)
1.0.0[src]
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); }
pub fn swap_remove(&mut self, index: usize) -> T
1.0.0[src]
Removes an element from the vector and returns it.
The removed element is replaced by the last element of the vector.
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"]);
pub fn insert(&mut self, index: usize, element: T)
1.0.0[src]
Inserts an element at position index
within the vector, shifting all
elements after it to the right.
Panics
Panics if index > len
.
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]);
pub fn remove(&mut self, index: usize) -> T
1.0.0[src]
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]);
pub fn retain<F>(&mut self, f: F) where
F: FnMut(&T) -> bool,
1.0.0[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
.
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]);
pub fn dedup_by_key<F, K>(&mut self, key: F) where
F: FnMut(&mut T) -> K,
K: PartialEq<K>,
1.16.0[src]
F: FnMut(&mut T) -> K,
K: PartialEq<K>,
Removes all but the first of consecutive elements in the vector that resolve to the same key.
If the vector is sorted, this removes all duplicates.
Examples
let mut vec = vec![10, 20, 21, 30, 20]; vec.dedup_by_key(|i| *i / 10); assert_eq!(vec, [10, 20, 30, 20]);
pub fn dedup_by<F>(&mut self, same_bucket: F) where
F: FnMut(&mut T, &mut T) -> bool,
1.16.0[src]
F: FnMut(&mut T, &mut T) -> bool,
Removes all but the first of consecutive elements in the vector satisfying a given equality relation.
The same_bucket
function is passed references to two elements from the vector, and
returns true
if the elements compare equal, or false
if they do not. The elements are
passed in opposite order from their order in the vector, so if same_bucket(a, b)
returns
true
, a
is removed.
If the vector is sorted, this removes all duplicates.
Examples
let mut vec = vec!["foo", "bar", "Bar", "baz", "bar"]; vec.dedup_by(|a, b| a.eq_ignore_ascii_case(b)); assert_eq!(vec, ["foo", "bar", "baz", "bar"]);
pub fn push(&mut self, value: T)
1.0.0[src]
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]);
pub fn place_back(&mut self) -> PlaceBack<T>
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🔬 This is a nightly-only experimental API. (collection_placement
)
placement protocol is subject to change
Returns a place for insertion at the back of the Vec
.
Using this method with placement syntax is equivalent to push
,
but may be more efficient.
Examples
#![feature(collection_placement)] #![feature(placement_in_syntax)] let mut vec = vec![1, 2]; vec.place_back() <- 3; vec.place_back() <- 4; assert_eq!(&vec, &[1, 2, 3, 4]);
pub fn pop(&mut self) -> Option<T>
1.0.0[src]
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]);
pub fn append(&mut self, other: &mut Vec<T>)
1.4.0[src]
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, []);
ⓘImportant traits for Drain<'a, T>pub fn drain<R>(&mut self, range: R) -> Drain<T> where
R: RangeArgument<usize>,
1.6.0[src]
R: RangeArgument<usize>,
Creates 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 only partially consumed or not consumed at all.
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, &[]);
pub fn clear(&mut self)
1.0.0[src]
Clears the vector, removing all values.
Note that this method has no effect on the allocated capacity of the vector.
Examples
let mut v = vec![1, 2, 3]; v.clear(); assert!(v.is_empty());
pub fn len(&self) -> usize
1.0.0[src]
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
1.0.0[src]
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());
pub fn split_off(&mut self, at: usize) -> Vec<T>
1.4.0[src]
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]);
pub fn resize(&mut self, new_len: usize, value: T)
1.5.0[src]
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.
This method requires Clone
to be able clone the passed value. If
you'd rather create a value with Default
instead, see
resize_default
.
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]);
pub fn extend_from_slice(&mut self, other: &[T])
1.6.0[src]
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]);
pub fn resize_default(&mut self, new_len: usize)
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vec_resize_default
)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 Default::default()
.
If new_len
is less than len
, the Vec
is simply truncated.
This method uses Default
to create new values on every push. If
you'd rather Clone
a given value, use resize
.
Examples
#![feature(vec_resize_default)] let mut vec = vec![1, 2, 3]; vec.resize_default(5); assert_eq!(vec, [1, 2, 3, 0, 0]); let mut vec = vec![1, 2, 3, 4]; vec.resize_default(2); assert_eq!(vec, [1, 2]);
pub fn dedup(&mut self)
1.0.0[src]
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]);
pub fn remove_item(&mut self, item: &T) -> Option<T>
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🔬 This is a nightly-only experimental API. (vec_remove_item
)
recently added
Removes the first instance of item
from the vector if the item exists.
Examples
let mut vec = vec![1, 2, 3, 1]; vec.remove_item(&1); assert_eq!(vec, vec![2, 3, 1]);
ⓘImportant traits for Splice<'a, I>pub fn splice<R, I>(
&mut self,
range: R,
replace_with: I
) -> Splice<<I as IntoIterator>::IntoIter> where
I: IntoIterator<Item = T>,
R: RangeArgument<usize>,
1.21.0[src]
&mut self,
range: R,
replace_with: I
) -> Splice<<I as IntoIterator>::IntoIter> where
I: IntoIterator<Item = T>,
R: RangeArgument<usize>,
Creates a splicing iterator that replaces the specified range in the vector
with the given replace_with
iterator and yields the removed items.
replace_with
does not need to be the same length as range
.
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 Splice
value is leaked.
Note 3: The input iterator replace_with
is only consumed
when the Splice
value is dropped.
Note 4: This is optimal if:
- The tail (elements in the vector after
range
) is empty, - or
replace_with
yields fewer elements thanrange
’s length - or the lower bound of its
size_hint()
is exact.
Otherwise, a temporary vector is allocated and the tail is moved twice.
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 new = [7, 8]; let u: Vec<_> = v.splice(..2, new.iter().cloned()).collect(); assert_eq!(v, &[7, 8, 3]); assert_eq!(u, &[1, 2]);
ⓘImportant traits for DrainFilter<'a, T, F>pub fn drain_filter<F>(&mut self, filter: F) -> DrainFilter<T, F> where
F: FnMut(&mut T) -> bool,
[src]
F: FnMut(&mut T) -> bool,
🔬 This is a nightly-only experimental API. (drain_filter
)
recently added
Creates an iterator which uses a closure to determine if an element should be removed.
If the closure returns true, then the element is removed and yielded. If the closure returns false, the element will remain in the vector and will not be yielded by the iterator.
Using this method is equivalent to the following code:
let mut i = 0; while i != vec.len() { if some_predicate(&mut vec[i]) { let val = vec.remove(i); // your code here } else { i += 1; } }
But drain_filter
is easier to use. drain_filter
is also more efficient,
because it can backshift the elements of the array in bulk.
Note that drain_filter
also lets you mutate every element in the filter closure,
regardless of whether you choose to keep or remove it.
Examples
Splitting an array into evens and odds, reusing the original allocation:
#![feature(drain_filter)] let mut numbers = vec![1, 2, 3, 4, 5, 6, 8, 9, 11, 13, 14, 15]; let evens = numbers.drain_filter(|x| *x % 2 == 0).collect::<Vec<_>>(); let odds = numbers; assert_eq!(evens, vec![2, 4, 6, 8, 14]); assert_eq!(odds, vec![1, 3, 5, 9, 11, 13, 15]);
Trait Implementations
impl Clone for Literal
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fn clone(&self) -> Literal
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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 Eq for Literal
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impl Ord for Literal
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fn cmp(&self, __arg_0: &Literal) -> Ordering
[src]
This method returns an Ordering
between self
and other
. Read more
fn max(self, other: Self) -> Self
1.21.0[src]
Compares and returns the maximum of two values. Read more
fn min(self, other: Self) -> Self
1.21.0[src]
Compares and returns the minimum of two values. Read more
impl PartialEq for Literal
[src]
fn eq(&self, other: &Literal) -> bool
[src]
This method tests for self
and other
values to be equal, and is used by ==
. Read more
fn ne(&self, other: &Rhs) -> bool
1.0.0[src]
This method tests for !=
.
impl PartialOrd for Literal
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fn partial_cmp(&self, other: &Literal) -> Option<Ordering>
[src]
This method returns an ordering between self
and other
values if one exists. Read more
fn lt(&self, other: &Rhs) -> bool
1.0.0[src]
This method tests less than (for self
and other
) and is used by the <
operator. Read more
fn le(&self, other: &Rhs) -> bool
1.0.0[src]
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
fn gt(&self, other: &Rhs) -> bool
1.0.0[src]
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
fn ge(&self, other: &Rhs) -> bool
1.0.0[src]
This method tests greater than or equal to (for self
and other
) and is used by the >=
operator. Read more
impl Debug for Literal
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fn fmt(&self, f: &mut Formatter) -> Result
[src]
Formats the value using the given formatter. Read more
impl AsRef<[u8]> for Literal
[src]
impl Deref for Literal
[src]
type Target = Vec<u8>
The resulting type after dereferencing.
fn deref(&self) -> &Vec<u8>
[src]
Dereferences the value.