1 files changed, 125 insertions, 1 deletions

diff --git a/src/libcore/str/mod.rs b/src/libcore/str/mod.rs
index eefed517330..5a20e32a419 100644
--- a/src/libcore/str/mod.rs
+++ b/src/libcore/str/mod.rs
@@ -8,10 +8,13 @@ use self::pattern::Pattern;
 use self::pattern::{Searcher, ReverseSearcher, DoubleEndedSearcher};
 
 use char;
-use fmt;
+use fmt::{self, Write};
 use iter::{Map, Cloned, FusedIterator, TrustedLen, TrustedRandomAccess, Filter};
+use iter::{Flatten, FlatMap, Chain};
 use slice::{self, SliceIndex, Split as SliceSplit};
 use mem;
+use ops::Try;
+use option;
 
 pub mod pattern;
 
@@ -3945,6 +3948,56 @@ impl str {
         let me = unsafe { self.as_bytes_mut() };
         me.make_ascii_lowercase()
     }
+
+    /// Escapes each char in `s` with [`char::escape_debug`].
+    ///
+    /// Note: only extended grapheme codepoints that begin the string will be
+    /// escaped.
+    ///
+    /// [`char::escape_debug`]: ../std/primitive.char.html#method.escape_debug
+    #[stable(feature = "str_escape", since = "1.34.0")]
+    pub fn escape_debug(&self) -> EscapeDebug {
+        let mut chars = self.chars();
+        EscapeDebug {
+            inner: chars.next()
+                .map(|first| first.escape_debug_ext(true))
+                .into_iter()
+                .flatten()
+                .chain(chars.flat_map(CharEscapeDebugContinue))
+        }
+    }
+
+    /// Escapes each char in `s` with [`char::escape_default`].
+    ///
+    /// [`char::escape_default`]: ../std/primitive.char.html#method.escape_default
+    #[stable(feature = "str_escape", since = "1.34.0")]
+    pub fn escape_default(&self) -> EscapeDefault {
+        EscapeDefault { inner: self.chars().flat_map(CharEscapeDefault) }
+    }
+
+    /// Escapes each char in `s` with [`char::escape_unicode`].
+    ///
+    /// [`char::escape_unicode`]: ../std/primitive.char.html#method.escape_unicode
+    #[stable(feature = "str_escape", since = "1.34.0")]
+    pub fn escape_unicode(&self) -> EscapeUnicode {
+        EscapeUnicode { inner: self.chars().flat_map(CharEscapeUnicode) }
+    }
+}
+
+impl_fn_for_zst! {
+    #[derive(Clone)]
+    struct CharEscapeDebugContinue impl Fn = |c: char| -> char::EscapeDebug {
+        c.escape_debug_ext(false)
+    };
+
+    #[derive(Clone)]
+    struct CharEscapeUnicode impl Fn = |c: char| -> char::EscapeUnicode {
+        c.escape_unicode()
+    };
+    #[derive(Clone)]
+    struct CharEscapeDefault impl Fn = |c: char| -> char::EscapeDefault {
+        c.escape_default()
+    };
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -4131,3 +4184,74 @@ impl<'a> Iterator for EncodeUtf16<'a> {
 
 #[stable(feature = "fused", since = "1.26.0")]
 impl FusedIterator for EncodeUtf16<'_> {}
+
+/// The return type of [`str::escape_debug`].
+///
+/// [`str::escape_debug`]: ../../std/primitive.str.html#method.escape_debug
+#[stable(feature = "str_escape", since = "1.34.0")]
+#[derive(Clone, Debug)]
+pub struct EscapeDebug<'a> {
+    inner: Chain<
+        Flatten<option::IntoIter<char::EscapeDebug>>,
+        FlatMap<Chars<'a>, char::EscapeDebug, CharEscapeDebugContinue>
+    >,
+}
+
+/// The return type of [`str::escape_default`].
+///
+/// [`str::escape_default`]: ../../std/primitive.str.html#method.escape_default
+#[stable(feature = "str_escape", since = "1.34.0")]
+#[derive(Clone, Debug)]
+pub struct EscapeDefault<'a> {
+    inner: FlatMap<Chars<'a>, char::EscapeDefault, CharEscapeDefault>,
+}
+
+/// The return type of [`str::escape_unicode`].
+///
+/// [`str::escape_unicode`]: ../../std/primitive.str.html#method.escape_unicode
+#[stable(feature = "str_escape", since = "1.34.0")]
+#[derive(Clone, Debug)]
+pub struct EscapeUnicode<'a> {
+    inner: FlatMap<Chars<'a>, char::EscapeUnicode, CharEscapeUnicode>,
+}
+
+macro_rules! escape_types_impls {
+    ($( $Name: ident ),+) => {$(
+        #[stable(feature = "str_escape", since = "1.34.0")]
+        impl<'a> fmt::Display for $Name<'a> {
+            fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+                self.clone().try_for_each(|c| f.write_char(c))
+            }
+        }
+
+        #[stable(feature = "str_escape", since = "1.34.0")]
+        impl<'a> Iterator for $Name<'a> {
+            type Item = char;
+
+            #[inline]
+            fn next(&mut self) -> Option<char> { 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
+                Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: 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)
+            }
+        }
+
+        #[stable(feature = "str_escape", since = "1.34.0")]
+        impl<'a> FusedIterator for $Name<'a> {}
+    )+}
+}
+
+escape_types_impls!(EscapeDebug, EscapeDefault, EscapeUnicode);