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Rollup merge of rust-lang#83130 - clarfonthey:escape, r=m-ou-se
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escape_ascii take 2

The previous PR, rust-lang#73111 was closed for inactivity; since I've had trouble in the past reopening closed PRs, I'm just making a new one.

I'm still running the tests locally but figured I'd open the PR in the meantime. Will fix whatever errors show up so we don't have to wait again for this.

r? `@m-ou-se`
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Dylan-DPC authored Mar 27, 2021
2 parents c1dc467 + 77a5fe9 commit 118a52b
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26 changes: 26 additions & 0 deletions library/core/src/num/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@

#![stable(feature = "rust1", since = "1.0.0")]

use crate::ascii;
use crate::intrinsics;
use crate::mem;
use crate::str::FromStr;
Expand Down Expand Up @@ -661,6 +662,31 @@ impl u8 {
pub const fn is_ascii_control(&self) -> bool {
matches!(*self, b'\0'..=b'\x1F' | b'\x7F')
}

/// Returns an iterator that produces an escaped version of a `u8`,
/// treating it as an ASCII character.
///
/// The behavior is identical to [`ascii::escape_default`].
///
/// # Examples
///
/// ```
/// #![feature(inherent_ascii_escape)]
///
/// assert_eq!("0", b'0'.escape_ascii().to_string());
/// assert_eq!("\\t", b'\t'.escape_ascii().to_string());
/// assert_eq!("\\r", b'\r'.escape_ascii().to_string());
/// assert_eq!("\\n", b'\n'.escape_ascii().to_string());
/// assert_eq!("\\'", b'\''.escape_ascii().to_string());
/// assert_eq!("\\\"", b'"'.escape_ascii().to_string());
/// assert_eq!("\\\\", b'\\'.escape_ascii().to_string());
/// assert_eq!("\\x9d", b'\x9d'.escape_ascii().to_string());
/// ```
#[unstable(feature = "inherent_ascii_escape", issue = "77174")]
#[inline]
pub fn escape_ascii(&self) -> ascii::EscapeDefault {
ascii::escape_default(*self)
}
}

#[lang = "u16"]
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93 changes: 93 additions & 0 deletions library/core/src/slice/ascii.rs
Original file line number Diff line number Diff line change
@@ -1,6 +1,10 @@
//! Operations on ASCII `[u8]`.

use crate::ascii;
use crate::fmt::{self, Write};
use crate::iter;
use crate::mem;
use crate::ops;

#[lang = "slice_u8"]
#[cfg(not(test))]
Expand Down Expand Up @@ -55,6 +59,95 @@ impl [u8] {
byte.make_ascii_lowercase();
}
}

/// Returns an iterator that produces an escaped version of this slice,
/// treating it as an ASCII string.
///
/// # Examples
///
/// ```
/// #![feature(inherent_ascii_escape)]
///
/// let s = b"0\t\r\n'\"\\\x9d";
/// let escaped = s.escape_ascii().to_string();
/// assert_eq!(escaped, "0\\t\\r\\n\\'\\\"\\\\\\x9d");
/// ```
#[unstable(feature = "inherent_ascii_escape", issue = "77174")]
pub fn escape_ascii(&self) -> EscapeAscii<'_> {
EscapeAscii { inner: self.iter().flat_map(EscapeByte) }
}
}

impl_fn_for_zst! {
#[derive(Clone)]
struct EscapeByte impl Fn = |byte: &u8| -> ascii::EscapeDefault {
ascii::escape_default(*byte)
};
}

/// An iterator over the escaped version of a byte slice.
///
/// This `struct` is created by the [`slice::escape_ascii`] method. See its
/// documentation for more information.
#[unstable(feature = "inherent_ascii_escape", issue = "77174")]
#[derive(Clone)]
pub struct EscapeAscii<'a> {
inner: iter::FlatMap<super::Iter<'a, u8>, ascii::EscapeDefault, EscapeByte>,
}

#[unstable(feature = "inherent_ascii_escape", issue = "77174")]
impl<'a> iter::Iterator for EscapeAscii<'a> {
type Item = u8;
#[inline]
fn next(&mut self) -> Option<u8> {
self.inner.next()
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
self.inner.size_hint()
}
#[inline]
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R
where
Fold: FnMut(Acc, Self::Item) -> R,
R: ops::Try<Ok = Acc>,
{
self.inner.try_fold(init, fold)
}
#[inline]
fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
where
Fold: FnMut(Acc, Self::Item) -> Acc,
{
self.inner.fold(init, fold)
}
#[inline]
fn last(mut self) -> Option<u8> {
self.next_back()
}
}

#[unstable(feature = "inherent_ascii_escape", issue = "77174")]
impl<'a> iter::DoubleEndedIterator for EscapeAscii<'a> {
fn next_back(&mut self) -> Option<u8> {
self.inner.next_back()
}
}
#[unstable(feature = "inherent_ascii_escape", issue = "77174")]
impl<'a> iter::ExactSizeIterator for EscapeAscii<'a> {}
#[unstable(feature = "inherent_ascii_escape", issue = "77174")]
impl<'a> iter::FusedIterator for EscapeAscii<'a> {}
#[unstable(feature = "inherent_ascii_escape", issue = "77174")]
impl<'a> fmt::Display for EscapeAscii<'a> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.clone().try_for_each(|b| f.write_char(b as char))
}
}
#[unstable(feature = "inherent_ascii_escape", issue = "77174")]
impl<'a> fmt::Debug for EscapeAscii<'a> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.pad("EscapeAscii { .. }")
}
}

/// Returns `true` if any byte in the word `v` is nonascii (>= 128). Snarfed
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3 changes: 3 additions & 0 deletions library/core/src/slice/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -81,6 +81,9 @@ pub use index::SliceIndex;
#[unstable(feature = "slice_range", issue = "76393")]
pub use index::range;

#[unstable(feature = "inherent_ascii_escape", issue = "77174")]
pub use ascii::EscapeAscii;

#[lang = "slice"]
#[cfg(not(test))]
impl<T> [T] {
Expand Down

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