/
str.rs
1501 lines (1425 loc) · 47.6 KB
/
str.rs
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// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! Unicode string slices
//!
//! *[See also the `str` primitive type](../primitive.str.html).*
#![stable(feature = "rust1", since = "1.0.0")]
// Many of the usings in this module are only used in the test configuration.
// It's cleaner to just turn off the unused_imports warning than to fix them.
#![allow(unused_imports)]
use core::clone::Clone;
use core::iter::{Iterator, Extend};
use core::option::Option::{self, Some, None};
use core::result::Result;
use core::str as core_str;
use core::str::pattern::Pattern;
use core::str::pattern::{Searcher, ReverseSearcher, DoubleEndedSearcher};
use core::mem;
use rustc_unicode::str::{UnicodeStr, Utf16Encoder};
use vec_deque::VecDeque;
use borrow::{Borrow, ToOwned};
use string::String;
use rustc_unicode;
use vec::Vec;
use slice::SliceConcatExt;
use boxed::Box;
pub use core::str::{FromStr, Utf8Error};
#[allow(deprecated)]
pub use core::str::{Lines, LinesAny, CharRange};
pub use core::str::{Split, RSplit};
pub use core::str::{SplitN, RSplitN};
pub use core::str::{SplitTerminator, RSplitTerminator};
pub use core::str::{Matches, RMatches};
pub use core::str::{MatchIndices, RMatchIndices};
pub use core::str::{from_utf8, Chars, CharIndices, Bytes};
pub use core::str::{from_utf8_unchecked, ParseBoolError};
pub use rustc_unicode::str::{SplitWhitespace};
pub use core::str::pattern;
impl<S: Borrow<str>> SliceConcatExt<str> for [S] {
type Output = String;
fn concat(&self) -> String {
if self.is_empty() {
return String::new();
}
// `len` calculation may overflow but push_str will check boundaries
let len = self.iter().map(|s| s.borrow().len()).sum();
let mut result = String::with_capacity(len);
for s in self {
result.push_str(s.borrow())
}
result
}
fn join(&self, sep: &str) -> String {
if self.is_empty() {
return String::new();
}
// concat is faster
if sep.is_empty() {
return self.concat();
}
// this is wrong without the guarantee that `self` is non-empty
// `len` calculation may overflow but push_str but will check boundaries
let len = sep.len() * (self.len() - 1)
+ self.iter().map(|s| s.borrow().len()).sum::<usize>();
let mut result = String::with_capacity(len);
let mut first = true;
for s in self {
if first {
first = false;
} else {
result.push_str(sep);
}
result.push_str(s.borrow());
}
result
}
fn connect(&self, sep: &str) -> String {
self.join(sep)
}
}
/// External iterator for a string's UTF-16 code units.
///
/// For use with the `std::iter` module.
#[derive(Clone)]
#[unstable(feature = "str_utf16", issue = "27714")]
pub struct Utf16Units<'a> {
encoder: Utf16Encoder<Chars<'a>>
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<'a> Iterator for Utf16Units<'a> {
type Item = u16;
#[inline]
fn next(&mut self) -> Option<u16> { self.encoder.next() }
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) { self.encoder.size_hint() }
}
// Return the initial codepoint accumulator for the first byte.
// The first byte is special, only want bottom 5 bits for width 2, 4 bits
// for width 3, and 3 bits for width 4
macro_rules! utf8_first_byte {
($byte:expr, $width:expr) => (($byte & (0x7F >> $width)) as u32)
}
// return the value of $ch updated with continuation byte $byte
macro_rules! utf8_acc_cont_byte {
($ch:expr, $byte:expr) => (($ch << 6) | ($byte & 63) as u32)
}
#[stable(feature = "rust1", since = "1.0.0")]
impl Borrow<str> for String {
#[inline]
fn borrow(&self) -> &str { &self[..] }
}
#[stable(feature = "rust1", since = "1.0.0")]
impl ToOwned for str {
type Owned = String;
fn to_owned(&self) -> String {
unsafe {
String::from_utf8_unchecked(self.as_bytes().to_owned())
}
}
}
/// Any string that can be represented as a slice.
#[lang = "str"]
#[cfg(not(test))]
#[stable(feature = "rust1", since = "1.0.0")]
impl str {
/// Returns the length of `self` in bytes.
///
/// # Examples
///
/// ```
/// assert_eq!("foo".len(), 3);
/// assert_eq!("ƒoo".len(), 4); // fancy f!
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn len(&self) -> usize {
core_str::StrExt::len(self)
}
/// Returns true if this slice has a length of zero bytes.
///
/// # Examples
///
/// ```
/// assert!("".is_empty());
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn is_empty(&self) -> bool {
core_str::StrExt::is_empty(self)
}
/// Checks that `index`-th byte lies at the start and/or end of a
/// UTF-8 code point sequence.
///
/// The start and end of the string (when `index == self.len()`) are
/// considered to be
/// boundaries.
///
/// Returns `false` if `index` is greater than `self.len()`.
///
/// # Examples
///
/// ```
/// #![feature(str_char)]
///
/// let s = "Löwe 老虎 Léopard";
/// assert!(s.is_char_boundary(0));
/// // start of `老`
/// assert!(s.is_char_boundary(6));
/// assert!(s.is_char_boundary(s.len()));
///
/// // second byte of `ö`
/// assert!(!s.is_char_boundary(2));
///
/// // third byte of `老`
/// assert!(!s.is_char_boundary(8));
/// ```
#[unstable(feature = "str_char",
reason = "it is unclear whether this method pulls its weight \
with the existence of the char_indices iterator or \
this method may want to be replaced with checked \
slicing",
issue = "27754")]
#[inline]
pub fn is_char_boundary(&self, index: usize) -> bool {
core_str::StrExt::is_char_boundary(self, index)
}
/// Converts `self` to a byte slice.
///
/// # Examples
///
/// ```
/// assert_eq!("bors".as_bytes(), b"bors");
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline(always)]
pub fn as_bytes(&self) -> &[u8] {
core_str::StrExt::as_bytes(self)
}
/// Returns a raw pointer to the `&str`'s buffer.
///
/// The caller must ensure that the string outlives this pointer, and
/// that it is not
/// reallocated (e.g. by pushing to the string).
///
/// # Examples
///
/// ```
/// let s = "Hello";
/// let p = s.as_ptr();
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn as_ptr(&self) -> *const u8 {
core_str::StrExt::as_ptr(self)
}
/// Takes a bytewise slice from a string.
///
/// Returns the substring from [`begin`..`end`).
///
/// # Unsafety
///
/// Caller must check both UTF-8 sequence boundaries and the boundaries
/// of the entire slice as well.
///
/// # Examples
///
/// ```
/// let s = "Löwe 老虎 Léopard";
///
/// unsafe {
/// assert_eq!(s.slice_unchecked(0, 21), "Löwe 老虎 Léopard");
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub unsafe fn slice_unchecked(&self, begin: usize, end: usize) -> &str {
core_str::StrExt::slice_unchecked(self, begin, end)
}
/// Takes a bytewise mutable slice from a string.
///
/// Same as `slice_unchecked`, but works with `&mut str` instead of `&str`.
#[unstable(feature = "str_slice_mut", reason = "recently added",
issue = "27793")]
#[inline]
pub unsafe fn slice_mut_unchecked(&mut self, begin: usize, end: usize) -> &mut str {
core_str::StrExt::slice_mut_unchecked(self, begin, end)
}
/// Given a byte position, return the next code point and its index.
///
/// This can be used to iterate over the Unicode code points of a string.
///
/// # Panics
///
/// If `i` is greater than or equal to the length of the string.
/// If `i` is not the index of the beginning of a valid UTF-8 sequence.
///
/// # Examples
///
/// This example manually iterates through the code points of a string;
/// this should normally be
/// done by `.chars()` or `.char_indices()`.
///
/// ```
/// #![feature(str_char, core)]
///
/// use std::str::CharRange;
///
/// let s = "中华Việt Nam";
/// let mut i = 0;
/// while i < s.len() {
/// let CharRange {ch, next} = s.char_range_at(i);
/// println!("{}: {}", i, ch);
/// i = next;
/// }
/// ```
///
/// This outputs:
///
/// ```text
/// 0: 中
/// 3: 华
/// 6: V
/// 7: i
/// 8: e
/// 9:
/// 11:
/// 13: t
/// 14:
/// 15: N
/// 16: a
/// 17: m
/// ```
#[unstable(feature = "str_char",
reason = "often replaced by char_indices, this method may \
be removed in favor of just char_at() or eventually \
removed altogether",
issue = "27754")]
#[inline]
pub fn char_range_at(&self, start: usize) -> CharRange {
core_str::StrExt::char_range_at(self, start)
}
/// Given a byte position, return the previous `char` and its position.
///
/// This function can be used to iterate over a Unicode code points in reverse.
///
/// Note that Unicode has many features, such as combining marks, ligatures,
/// and direction marks, that need to be taken into account to correctly reverse a string.
///
/// Returns 0 for next index if called on start index 0.
///
/// # Panics
///
/// If `i` is greater than the length of the string.
/// If `i` is not an index following a valid UTF-8 sequence.
///
/// # Examples
///
/// This example manually iterates through the code points of a string;
/// this should normally be
/// done by `.chars().rev()` or `.char_indices()`.
///
/// ```
/// #![feature(str_char, core)]
///
/// use std::str::CharRange;
///
/// let s = "中华Việt Nam";
/// let mut i = s.len();
/// while i > 0 {
/// let CharRange {ch, next} = s.char_range_at_reverse(i);
/// println!("{}: {}", i, ch);
/// i = next;
/// }
/// ```
///
/// This outputs:
///
/// ```text
/// 18: m
/// 17: a
/// 16: N
/// 15:
/// 14: t
/// 13:
/// 11:
/// 9: e
/// 8: i
/// 7: V
/// 6: 华
/// 3: 中
/// ```
#[unstable(feature = "str_char",
reason = "often replaced by char_indices, this method may \
be removed in favor of just char_at_reverse() or \
eventually removed altogether",
issue = "27754")]
#[inline]
pub fn char_range_at_reverse(&self, start: usize) -> CharRange {
core_str::StrExt::char_range_at_reverse(self, start)
}
/// Given a byte position, return the `char` at that position.
///
/// # Panics
///
/// If `i` is greater than or equal to the length of the string.
/// If `i` is not the index of the beginning of a valid UTF-8 sequence.
///
/// # Examples
///
/// ```
/// #![feature(str_char)]
///
/// let s = "abπc";
/// assert_eq!(s.char_at(1), 'b');
/// assert_eq!(s.char_at(2), 'π');
/// assert_eq!(s.char_at(4), 'c');
/// ```
#[unstable(feature = "str_char",
reason = "frequently replaced by the chars() iterator, this \
method may be removed or possibly renamed in the \
future; it is normally replaced by chars/char_indices \
iterators or by getting the first char from a \
subslice",
issue = "27754")]
#[inline]
pub fn char_at(&self, i: usize) -> char {
core_str::StrExt::char_at(self, i)
}
/// Given a byte position, return the `char` at that position, counting
/// from the end.
///
/// # Panics
///
/// If `i` is greater than the length of the string.
/// If `i` is not an index following a valid UTF-8 sequence.
///
/// # Examples
///
/// ```
/// #![feature(str_char)]
///
/// let s = "abπc";
/// assert_eq!(s.char_at_reverse(1), 'a');
/// assert_eq!(s.char_at_reverse(2), 'b');
/// assert_eq!(s.char_at_reverse(3), 'π');
/// ```
#[unstable(feature = "str_char",
reason = "see char_at for more details, but reverse semantics \
are also somewhat unclear, especially with which \
cases generate panics",
issue = "27754")]
#[inline]
pub fn char_at_reverse(&self, i: usize) -> char {
core_str::StrExt::char_at_reverse(self, i)
}
/// Retrieves the first code point from a `&str` and returns it.
///
/// Note that a single Unicode character (grapheme cluster)
/// can be composed of multiple `char`s.
///
/// This does not allocate a new string; instead, it returns a slice that
/// points one code point beyond the code point that was shifted.
///
/// `None` is returned if the slice is empty.
///
/// # Examples
///
/// ```
/// #![feature(str_char)]
///
/// let s = "Łódź"; // \u{141}o\u{301}dz\u{301}
/// let (c, s1) = s.slice_shift_char().unwrap();
///
/// assert_eq!(c, 'Ł');
/// assert_eq!(s1, "ódź");
///
/// let (c, s2) = s1.slice_shift_char().unwrap();
///
/// assert_eq!(c, 'o');
/// assert_eq!(s2, "\u{301}dz\u{301}");
/// ```
#[unstable(feature = "str_char",
reason = "awaiting conventions about shifting and slices and \
may not be warranted with the existence of the chars \
and/or char_indices iterators",
issue = "27754")]
#[inline]
pub fn slice_shift_char(&self) -> Option<(char, &str)> {
core_str::StrExt::slice_shift_char(self)
}
/// Divide one string slice into two at an index.
///
/// The index `mid` is a byte offset from the start of the string
/// that must be on a `char` boundary.
///
/// Return slices `&self[..mid]` and `&self[mid..]`.
///
/// # Panics
///
/// Panics if `mid` is beyond the last code point of the string,
/// or if it is not on a `char` boundary.
///
/// # Examples
/// ```
/// let s = "Löwe 老虎 Léopard";
/// let first_space = s.find(' ').unwrap_or(s.len());
/// let (a, b) = s.split_at(first_space);
///
/// assert_eq!(a, "Löwe");
/// assert_eq!(b, " 老虎 Léopard");
/// ```
#[inline]
#[stable(feature = "str_split_at", since = "1.4.0")]
pub fn split_at(&self, mid: usize) -> (&str, &str) {
core_str::StrExt::split_at(self, mid)
}
/// Divide one mutable string slice into two at an index.
#[inline]
#[stable(feature = "str_split_at", since = "1.4.0")]
pub fn split_at_mut(&mut self, mid: usize) -> (&mut str, &mut str) {
core_str::StrExt::split_at_mut(self, mid)
}
/// An iterator over the code points of `self`.
///
/// In Unicode relationship between code points and characters is complex.
/// A single character may be composed of multiple code points
/// (e.g. diacritical marks added to a letter), and a single code point
/// (e.g. Hangul syllable) may contain multiple characters.
///
/// For iteration over human-readable characters a grapheme cluster iterator
/// may be more appropriate. See the [unicode-segmentation crate][1].
///
/// [1]: https://crates.io/crates/unicode-segmentation
///
/// # Examples
///
/// ```
/// let v: Vec<char> = "ASCII żółć 🇨🇭 한".chars().collect();
///
/// assert_eq!(v, ['A', 'S', 'C', 'I', 'I', ' ',
/// 'z', '\u{307}', 'o', '\u{301}', 'ł', 'c', '\u{301}', ' ',
/// '\u{1f1e8}', '\u{1f1ed}', ' ', '한']);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn chars(&self) -> Chars {
core_str::StrExt::chars(self)
}
/// An iterator over the `char`s of `self` and their byte offsets.
///
/// # Examples
///
/// ```
/// let v: Vec<(usize, char)> = "A🇨🇭".char_indices().collect();
/// let b = vec![(0, 'A'), (1, '\u{1f1e8}'), (5, '\u{1f1ed}')];
///
/// assert_eq!(v, b);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn char_indices(&self) -> CharIndices {
core_str::StrExt::char_indices(self)
}
/// An iterator over the bytes of `self`.
///
/// # Examples
///
/// ```
/// let v: Vec<u8> = "bors".bytes().collect();
///
/// assert_eq!(v, b"bors".to_vec());
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn bytes(&self) -> Bytes {
core_str::StrExt::bytes(self)
}
/// An iterator over the non-empty substrings of `self` which contain no whitespace,
/// and which are separated by any amount of whitespace.
///
/// # Examples
///
/// ```
/// let some_words = " Mary had\ta\u{2009}little \n\t lamb";
/// let v: Vec<&str> = some_words.split_whitespace().collect();
///
/// assert_eq!(v, ["Mary", "had", "a", "little", "lamb"]);
/// ```
#[stable(feature = "split_whitespace", since = "1.1.0")]
#[inline]
pub fn split_whitespace(&self) -> SplitWhitespace {
UnicodeStr::split_whitespace(self)
}
/// An iterator over the lines of a string, separated by `\n` or `\r\n`.
///
/// This does not include the empty string after a trailing newline or CRLF.
///
/// # Examples
///
/// ```
/// let four_lines = "foo\nbar\n\r\nbaz";
/// let v: Vec<&str> = four_lines.lines().collect();
///
/// assert_eq!(v, ["foo", "bar", "", "baz"]);
/// ```
///
/// Leaving off the trailing character:
///
/// ```
/// let four_lines = "foo\r\nbar\n\nbaz\n";
/// let v: Vec<&str> = four_lines.lines().collect();
///
/// assert_eq!(v, ["foo", "bar", "", "baz"]);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn lines(&self) -> Lines {
core_str::StrExt::lines(self)
}
/// An iterator over the lines of a string, separated by either
/// `\n` or `\r\n`.
///
/// As with `.lines()`, this does not include an empty trailing line.
///
/// # Examples
///
/// ```
/// let four_lines = "foo\r\nbar\n\r\nbaz";
/// let v: Vec<&str> = four_lines.lines_any().collect();
///
/// assert_eq!(v, ["foo", "bar", "", "baz"]);
/// ```
///
/// Leaving off the trailing character:
///
/// ```
/// let four_lines = "foo\r\nbar\n\r\nbaz\n";
/// let v: Vec<&str> = four_lines.lines_any().collect();
///
/// assert_eq!(v, ["foo", "bar", "", "baz"]);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[deprecated(since = "1.4.0", reason = "use lines() instead now")]
#[inline]
#[allow(deprecated)]
pub fn lines_any(&self) -> LinesAny {
core_str::StrExt::lines_any(self)
}
/// Returns an iterator of `u16` over the string encoded as UTF-16.
#[unstable(feature = "str_utf16",
reason = "this functionality may only be provided by libunicode",
issue = "27714")]
pub fn utf16_units(&self) -> Utf16Units {
Utf16Units { encoder: Utf16Encoder::new(self[..].chars()) }
}
/// Returns `true` if `self` contains another `&str`.
///
/// # Examples
///
/// ```
/// assert!("bananas".contains("nana"));
///
/// assert!(!"bananas".contains("foobar"));
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn contains<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool {
core_str::StrExt::contains(self, pat)
}
/// Returns `true` if the given `&str` is a prefix of the string.
///
/// # Examples
///
/// ```
/// assert!("banana".starts_with("ba"));
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn starts_with<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool {
core_str::StrExt::starts_with(self, pat)
}
/// Returns true if the given `&str` is a suffix of the string.
///
/// # Examples
///
/// ```rust
/// assert!("banana".ends_with("nana"));
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn ends_with<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool
where P::Searcher: ReverseSearcher<'a>
{
core_str::StrExt::ends_with(self, pat)
}
/// Returns the byte index of the first character of `self` that matches
/// the pattern, if it
/// exists.
///
/// Returns `None` if it doesn't exist.
///
/// The pattern can be a simple `&str`, `char`, or a closure that
/// determines if a character matches.
///
/// # Examples
///
/// Simple patterns:
///
/// ```
/// let s = "Löwe 老虎 Léopard";
///
/// assert_eq!(s.find('L'), Some(0));
/// assert_eq!(s.find('é'), Some(14));
/// assert_eq!(s.find("Léopard"), Some(13));
///
/// ```
///
/// More complex patterns with closures:
///
/// ```
/// let s = "Löwe 老虎 Léopard";
///
/// assert_eq!(s.find(char::is_whitespace), Some(5));
/// assert_eq!(s.find(char::is_lowercase), Some(1));
/// ```
///
/// Not finding the pattern:
///
/// ```
/// let s = "Löwe 老虎 Léopard";
/// let x: &[_] = &['1', '2'];
///
/// assert_eq!(s.find(x), None);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn find<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize> {
core_str::StrExt::find(self, pat)
}
/// Returns the byte index of the last character of `self` that
/// matches the pattern, if it
/// exists.
///
/// Returns `None` if it doesn't exist.
///
/// The pattern can be a simple `&str`, `char`,
/// or a closure that determines if a character matches.
///
/// # Examples
///
/// Simple patterns:
///
/// ```
/// let s = "Löwe 老虎 Léopard";
///
/// assert_eq!(s.rfind('L'), Some(13));
/// assert_eq!(s.rfind('é'), Some(14));
/// ```
///
/// More complex patterns with closures:
///
/// ```
/// let s = "Löwe 老虎 Léopard";
///
/// assert_eq!(s.rfind(char::is_whitespace), Some(12));
/// assert_eq!(s.rfind(char::is_lowercase), Some(20));
/// ```
///
/// Not finding the pattern:
///
/// ```
/// let s = "Löwe 老虎 Léopard";
/// let x: &[_] = &['1', '2'];
///
/// assert_eq!(s.rfind(x), None);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn rfind<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize>
where P::Searcher: ReverseSearcher<'a>
{
core_str::StrExt::rfind(self, pat)
}
/// An iterator over substrings of `self`, separated by characters
/// matched by a pattern.
///
/// The pattern can be a simple `&str`, `char`, or a closure that
/// determines the split. Additional libraries might provide more complex
/// patterns like regular expressions.
///
/// # Iterator behavior
///
/// The returned iterator will be double ended if the pattern allows a
/// reverse search and forward/reverse search yields the same elements.
/// This is true for, eg, `char` but not
/// for `&str`.
///
/// If the pattern allows a reverse search but its results might differ
/// from a forward search, `rsplit()` can be used.
///
/// # Examples
///
/// Simple patterns:
///
/// ```
/// let v: Vec<&str> = "Mary had a little lamb".split(' ').collect();
/// assert_eq!(v, ["Mary", "had", "a", "little", "lamb"]);
///
/// let v: Vec<&str> = "".split('X').collect();
/// assert_eq!(v, [""]);
///
/// let v: Vec<&str> = "lionXXtigerXleopard".split('X').collect();
/// assert_eq!(v, ["lion", "", "tiger", "leopard"]);
///
/// let v: Vec<&str> = "lion::tiger::leopard".split("::").collect();
/// assert_eq!(v, ["lion", "tiger", "leopard"]);
///
/// let v: Vec<&str> = "abc1def2ghi".split(char::is_numeric).collect();
/// assert_eq!(v, ["abc", "def", "ghi"]);
///
/// let v: Vec<&str> = "lionXtigerXleopard".split(char::is_uppercase).collect();
/// assert_eq!(v, ["lion", "tiger", "leopard"]);
/// ```
///
/// A more complex pattern, using a closure:
///
/// ```
/// let v: Vec<&str> = "abc1defXghi".split(|c| c == '1' || c == 'X').collect();
/// assert_eq!(v, ["abc", "def", "ghi"]);
/// ```
///
/// If a string contains multiple contiguous separators, you will end up
/// with empty strings in the output:
///
/// ```
/// let x = "||||a||b|c".to_string();
/// let d: Vec<_> = x.split('|').collect();
///
/// assert_eq!(d, &["", "", "", "", "a", "", "b", "c"]);
/// ```
///
/// This can lead to possibly surprising behavior when whitespace is used
/// as the separator. This code is correct:
///
/// ```
/// let x = " a b c".to_string();
/// let d: Vec<_> = x.split(' ').collect();
///
/// assert_eq!(d, &["", "", "", "", "a", "", "b", "c"]);
/// ```
///
/// It does _not_ give you:
///
/// ```rust,ignore
/// assert_eq!(d, &["a", "b", "c"]);
/// ```
///
/// Use [`.split_whitespace()`][split_whitespace] for this behavior.
///
/// [split_whitespace]: #method.split_whitespace
#[stable(feature = "rust1", since = "1.0.0")]
pub fn split<'a, P: Pattern<'a>>(&'a self, pat: P) -> Split<'a, P> {
core_str::StrExt::split(self, pat)
}
/// An iterator over substrings of `self`, separated by characters
/// matched by a pattern and yielded in reverse order.
///
/// The pattern can be a simple `&str`, `char`, or a closure that
/// determines the split.
/// Additional libraries might provide more complex patterns like
/// regular expressions.
///
/// # Iterator behavior
///
/// The returned iterator requires that the pattern supports a
/// reverse search,
/// and it will be double ended if a forward/reverse search yields
/// the same elements.
///
/// For iterating from the front, `split()` can be used.
///
/// # Examples
///
/// Simple patterns:
///
/// ```rust
/// let v: Vec<&str> = "Mary had a little lamb".rsplit(' ').collect();
/// assert_eq!(v, ["lamb", "little", "a", "had", "Mary"]);
///
/// let v: Vec<&str> = "".rsplit('X').collect();
/// assert_eq!(v, [""]);
///
/// let v: Vec<&str> = "lionXXtigerXleopard".rsplit('X').collect();
/// assert_eq!(v, ["leopard", "tiger", "", "lion"]);
///
/// let v: Vec<&str> = "lion::tiger::leopard".rsplit("::").collect();
/// assert_eq!(v, ["leopard", "tiger", "lion"]);
/// ```
///
/// A more complex pattern, using a closure:
///
/// ```
/// let v: Vec<&str> = "abc1defXghi".rsplit(|c| c == '1' || c == 'X').collect();
/// assert_eq!(v, ["ghi", "def", "abc"]);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn rsplit<'a, P: Pattern<'a>>(&'a self, pat: P) -> RSplit<'a, P>
where P::Searcher: ReverseSearcher<'a>
{
core_str::StrExt::rsplit(self, pat)
}
/// An iterator over substrings of `self`, separated by characters
/// matched by a pattern.
///
/// The pattern can be a simple `&str`, `char`, or a closure that
/// determines the split.
/// Additional libraries might provide more complex patterns
/// like regular expressions.
///
/// Equivalent to `split`, except that the trailing substring
/// is skipped if empty.
///
/// This method can be used for string data that is _terminated_,
/// rather than _separated_ by a pattern.
///
/// # Iterator behavior
///
/// The returned iterator will be double ended if the pattern allows a
/// reverse search
/// and forward/reverse search yields the same elements. This is true
/// for, eg, `char` but not for `&str`.
///
/// If the pattern allows a reverse search but its results might differ
/// from a forward search, `rsplit_terminator()` can be used.
///
/// # Examples
///
/// ```
/// let v: Vec<&str> = "A.B.".split_terminator('.').collect();
/// assert_eq!(v, ["A", "B"]);
///
/// let v: Vec<&str> = "A..B..".split_terminator(".").collect();
/// assert_eq!(v, ["A", "", "B", ""]);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn split_terminator<'a, P: Pattern<'a>>(&'a self, pat: P) -> SplitTerminator<'a, P> {
core_str::StrExt::split_terminator(self, pat)
}
/// An iterator over substrings of `self`, separated by characters
/// matched by a pattern and yielded in reverse order.
///
/// The pattern can be a simple `&str`, `char`, or a closure that
/// determines the split.
/// Additional libraries might provide more complex patterns like
/// regular expressions.
///
/// Equivalent to `split`, except that the trailing substring is
/// skipped if empty.
///
/// This method can be used for string data that is _terminated_,
/// rather than _separated_ by a pattern.
///
/// # Iterator behavior
///
/// The returned iterator requires that the pattern supports a
/// reverse search, and it will be double ended if a forward/reverse
/// search yields the same elements.
///
/// For iterating from the front, `split_terminator()` can be used.
///
/// # Examples
///
/// ```
/// let v: Vec<&str> = "A.B.".rsplit_terminator('.').collect();
/// assert_eq!(v, ["B", "A"]);
///
/// let v: Vec<&str> = "A..B..".rsplit_terminator(".").collect();
/// assert_eq!(v, ["", "B", "", "A"]);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn rsplit_terminator<'a, P: Pattern<'a>>(&'a self, pat: P) -> RSplitTerminator<'a, P>
where P::Searcher: ReverseSearcher<'a>
{
core_str::StrExt::rsplit_terminator(self, pat)