std: Change escape_unicode to use new escapes

This changes the `escape_unicode` method on a `char` to use the new style of
unicode escapes in the language.

Closes #19811
Closes #19879

Author: alexcrichton

src/libcollections/str.rs

@@ -1597,17 +1597,24 @@ mod tests {
 
     #[test]
     fn test_escape_unicode() {
-        assert_eq!("abc".escape_unicode(), String::from_str("\\x61\\x62\\x63"));
-        assert_eq!("a c".escape_unicode(), String::from_str("\\x61\\x20\\x63"));
-        assert_eq!("\r\n\t".escape_unicode(), String::from_str("\\x0d\\x0a\\x09"));
-        assert_eq!("'\"\\".escape_unicode(), String::from_str("\\x27\\x22\\x5c"));
+        assert_eq!("abc".escape_unicode(),
+                   String::from_str("\\u{61}\\u{62}\\u{63}"));
+        assert_eq!("a c".escape_unicode(),
+                   String::from_str("\\u{61}\\u{20}\\u{63}"));
+        assert_eq!("\r\n\t".escape_unicode(),
+                   String::from_str("\\u{d}\\u{a}\\u{9}"));
+        assert_eq!("'\"\\".escape_unicode(),
+                   String::from_str("\\u{27}\\u{22}\\u{5c}"));
         assert_eq!("\x00\x01\u{fe}\u{ff}".escape_unicode(),
-                   String::from_str("\\x00\\x01\\u00fe\\u00ff"));
-        assert_eq!("\u{100}\u{ffff}".escape_unicode(), String::from_str("\\u0100\\uffff"));
+                   String::from_str("\\u{0}\\u{1}\\u{fe}\\u{ff}"));
+        assert_eq!("\u{100}\u{ffff}".escape_unicode(),
+                   String::from_str("\\u{100}\\u{ffff}"));
         assert_eq!("\u{10000}\u{10ffff}".escape_unicode(),
-                   String::from_str("\\U00010000\\U0010ffff"));
-        assert_eq!("ab\u{fb00}".escape_unicode(), String::from_str("\\x61\\x62\\ufb00"));
-        assert_eq!("\u{1d4ea}\r".escape_unicode(), String::from_str("\\U0001d4ea\\x0d"));
+                   String::from_str("\\u{10000}\\u{10ffff}"));
+        assert_eq!("ab\u{fb00}".escape_unicode(),
+                   String::from_str("\\u{61}\\u{62}\\u{fb00}"));
+        assert_eq!("\u{1d4ea}\r".escape_unicode(),
+                   String::from_str("\\u{1d4ea}\\u{d}"));
     }
 
     #[test]
@@ -1616,11 +1623,14 @@ mod tests {
         assert_eq!("a c".escape_default(), String::from_str("a c"));
         assert_eq!("\r\n\t".escape_default(), String::from_str("\\r\\n\\t"));
         assert_eq!("'\"\\".escape_default(), String::from_str("\\'\\\"\\\\"));
-        assert_eq!("\u{100}\u{ffff}".escape_default(), String::from_str("\\u0100\\uffff"));
+        assert_eq!("\u{100}\u{ffff}".escape_default(),
+                   String::from_str("\\u{100}\\u{ffff}"));
         assert_eq!("\u{10000}\u{10ffff}".escape_default(),
-                   String::from_str("\\U00010000\\U0010ffff"));
-        assert_eq!("ab\u{fb00}".escape_default(), String::from_str("ab\\ufb00"));
-        assert_eq!("\u{1d4ea}\r".escape_default(), String::from_str("\\U0001d4ea\\r"));
+                   String::from_str("\\u{10000}\\u{10ffff}"));
+        assert_eq!("ab\u{fb00}".escape_default(),
+                   String::from_str("ab\\u{fb00}"));
+        assert_eq!("\u{1d4ea}\r".escape_default(),
+                   String::from_str("\\u{1d4ea}\\r"));
     }
 
     #[test]

src/libcore/char.rs

@@ -15,11 +15,11 @@
 #![allow(non_snake_case)]
 #![doc(primitive = "char")]
 
+use iter::Iterator;
 use mem::transmute;
 use ops::FnMut;
-use option::Option;
 use option::Option::{None, Some};
-use iter::{range_step, Iterator, RangeStep};
+use option::Option;
 use slice::SliceExt;
 
 // UTF-8 ranges and tags for encoding characters
@@ -156,34 +156,15 @@ pub fn from_digit(num: uint, radix: uint) -> Option<char> {
     }
 }
 
-///
-/// Returns the hexadecimal Unicode escape of a `char`
-///
-/// The rules are as follows:
-///
-/// - chars in [0,0xff] get 2-digit escapes: `\\xNN`
-/// - chars in [0x100,0xffff] get 4-digit escapes: `\\u{NNNN}`
-/// - chars above 0x10000 get 8-digit escapes: `\\u{{NNN}NNNNN}`
-///
+/// Deprecated, call the escape_unicode method instead.
 #[deprecated = "use the Char::escape_unicode method"]
 pub fn escape_unicode<F>(c: char, mut f: F) where F: FnMut(char) {
     for char in c.escape_unicode() {
         f(char);
     }
 }
 
-///
-/// Returns a 'default' ASCII and C++11-like literal escape of a `char`
-///
-/// The default is chosen with a bias toward producing literals that are
-/// legal in a variety of languages, including C++11 and similar C-family
-/// languages. The exact rules are:
-///
-/// - Tab, CR and LF are escaped as '\t', '\r' and '\n' respectively.
-/// - Single-quote, double-quote and backslash chars are backslash-escaped.
-/// - Any other chars in the range [0x20,0x7e] are not escaped.
-/// - Any other chars are given hex Unicode escapes; see `escape_unicode`.
-///
+/// Deprecated, call the escape_default method instead.
 #[deprecated = "use the Char::escape_default method"]
 pub fn escape_default<F>(c: char, mut f: F) where F: FnMut(char) {
     for c in c.escape_default() {
@@ -267,13 +248,11 @@ pub trait Char {
     /// Returns an iterator that yields the hexadecimal Unicode escape
     /// of a character, as `char`s.
     ///
-    /// The rules are as follows:
-    ///
-    /// * Characters in [0,0xff] get 2-digit escapes: `\\xNN`
-    /// * Characters in [0x100,0xffff] get 4-digit escapes: `\\u{NNNN}`.
-    /// * Characters above 0x10000 get 8-digit escapes: `\\u{{NNN}NNNNN}`.
+    /// All characters are escaped with Rust syntax of the form `\\u{NNNN}`
+    /// where `NNNN` is the shortest hexadecimal representation of the code
+    /// point.
     #[unstable = "pending error conventions, trait organization"]
-    fn escape_unicode(self) -> UnicodeEscapedChars;
+    fn escape_unicode(self) -> EscapeUnicode;
 
     /// Returns an iterator that yields the 'default' ASCII and
     /// C++11-like literal escape of a character, as `char`s.
@@ -288,7 +267,7 @@ pub trait Char {
     /// * Any other chars in the range [0x20,0x7e] are not escaped.
     /// * Any other chars are given hex Unicode escapes; see `escape_unicode`.
     #[unstable = "pending error conventions, trait organization"]
-    fn escape_default(self) -> DefaultEscapedChars;
+    fn escape_default(self) -> EscapeDefault;
 
     /// Returns the amount of bytes this character would need if encoded in
     /// UTF-8.
@@ -358,23 +337,23 @@ impl Char for char {
     fn from_u32(i: u32) -> Option<char> { from_u32(i) }
 
     #[unstable = "pending error conventions, trait organization"]
-    fn escape_unicode(self) -> UnicodeEscapedChars {
-        UnicodeEscapedChars { c: self, state: UnicodeEscapedCharsState::Backslash }
+    fn escape_unicode(self) -> EscapeUnicode {
+        EscapeUnicode { c: self, state: EscapeUnicodeState::Backslash }
     }
 
     #[unstable = "pending error conventions, trait organization"]
-    fn escape_default(self) -> DefaultEscapedChars {
+    fn escape_default(self) -> EscapeDefault {
         let init_state = match self {
-            '\t' => DefaultEscapedCharsState::Backslash('t'),
-            '\r' => DefaultEscapedCharsState::Backslash('r'),
-            '\n' => DefaultEscapedCharsState::Backslash('n'),
-            '\\' => DefaultEscapedCharsState::Backslash('\\'),
-            '\'' => DefaultEscapedCharsState::Backslash('\''),
-            '"'  => DefaultEscapedCharsState::Backslash('"'),
-            '\x20' ... '\x7e' => DefaultEscapedCharsState::Char(self),
-            _ => DefaultEscapedCharsState::Unicode(self.escape_unicode())
+            '\t' => EscapeDefaultState::Backslash('t'),
+            '\r' => EscapeDefaultState::Backslash('r'),
+            '\n' => EscapeDefaultState::Backslash('n'),
+            '\\' => EscapeDefaultState::Backslash('\\'),
+            '\'' => EscapeDefaultState::Backslash('\''),
+            '"'  => EscapeDefaultState::Backslash('"'),
+            '\x20' ... '\x7e' => EscapeDefaultState::Char(self),
+            _ => EscapeDefaultState::Unicode(self.escape_unicode())
         };
-        DefaultEscapedChars { state: init_state }
+        EscapeDefault { state: init_state }
     }
 
     #[inline]
@@ -451,72 +430,86 @@ impl Char for char {
 
 /// An iterator over the characters that represent a `char`, as escaped by
 /// Rust's unicode escaping rules.
-pub struct UnicodeEscapedChars {
+pub struct EscapeUnicode {
     c: char,
-    state: UnicodeEscapedCharsState
+    state: EscapeUnicodeState
 }
 
-enum UnicodeEscapedCharsState {
+enum EscapeUnicodeState {
     Backslash,
     Type,
-    Value(RangeStep<i32>),
+    LeftBrace,
+    Value(uint),
+    RightBrace,
+    Done,
 }
 
-impl Iterator<char> for UnicodeEscapedChars {
+impl Iterator<char> for EscapeUnicode {
     fn next(&mut self) -> Option<char> {
         match self.state {
-            UnicodeEscapedCharsState::Backslash => {
-                self.state = UnicodeEscapedCharsState::Type;
+            EscapeUnicodeState::Backslash => {
+                self.state = EscapeUnicodeState::Type;
                 Some('\\')
             }
-            UnicodeEscapedCharsState::Type => {
-                let (typechar, pad) = if self.c <= '\x7f' { ('x', 2) }
-                                      else if self.c <= '\u{ffff}' { ('u', 4) }
-                                      else { ('U', 8) };
-                self.state = UnicodeEscapedCharsState::Value(range_step(4 * (pad - 1), -1, -4i32));
-                Some(typechar)
+            EscapeUnicodeState::Type => {
+                self.state = EscapeUnicodeState::LeftBrace;
+                Some('u')
             }
-            UnicodeEscapedCharsState::Value(ref mut range_step) => match range_step.next() {
-                Some(offset) => {
-                    let offset = offset as uint;
-                    let v = match ((self.c as i32) >> offset) & 0xf {
-                        i @ 0 ... 9 => '0' as i32 + i,
-                        i => 'a' as i32 + (i - 10)
-                    };
-                    Some(unsafe { transmute(v) })
+            EscapeUnicodeState::LeftBrace => {
+                let mut n = 0u;
+                while (self.c as u32) >> (4 * (n + 1)) != 0 {
+                    n += 1;
                 }
-                None => None
+                self.state = EscapeUnicodeState::Value(n);
+                Some('{')
+            }
+            EscapeUnicodeState::Value(offset) => {
+                let v = match ((self.c as i32) >> (offset * 4)) & 0xf {
+                    i @ 0 ... 9 => '0' as i32 + i,
+                    i => 'a' as i32 + (i - 10)
+                };
+                if offset == 0 {
+                    self.state = EscapeUnicodeState::RightBrace;
+                } else {
+                    self.state = EscapeUnicodeState::Value(offset - 1);
+                }
+                Some(unsafe { transmute(v) })
+            }
+            EscapeUnicodeState::RightBrace => {
+                self.state = EscapeUnicodeState::Done;
+                Some('}')
             }
+            EscapeUnicodeState::Done => None,
         }
     }
 }
 
 /// An iterator over the characters that represent a `char`, escaped
 /// for maximum portability.
-pub struct DefaultEscapedChars {
-    state: DefaultEscapedCharsState
+pub struct EscapeDefault {
+    state: EscapeDefaultState
 }
 
-enum DefaultEscapedCharsState {
+enum EscapeDefaultState {
     Backslash(char),
     Char(char),
     Done,
-    Unicode(UnicodeEscapedChars),
+    Unicode(EscapeUnicode),
 }
 
-impl Iterator<char> for DefaultEscapedChars {
+impl Iterator<char> for EscapeDefault {
     fn next(&mut self) -> Option<char> {
         match self.state {
-            DefaultEscapedCharsState::Backslash(c) => {
-                self.state = DefaultEscapedCharsState::Char(c);
+            EscapeDefaultState::Backslash(c) => {
+                self.state = EscapeDefaultState::Char(c);
                 Some('\\')
             }
-            DefaultEscapedCharsState::Char(c) => {
-                self.state = DefaultEscapedCharsState::Done;
+            EscapeDefaultState::Char(c) => {
+                self.state = EscapeDefaultState::Done;
                 Some(c)
             }
-            DefaultEscapedCharsState::Done => None,
-            DefaultEscapedCharsState::Unicode(ref mut iter) => iter.next()
+            EscapeDefaultState::Done => None,
+            EscapeDefaultState::Unicode(ref mut iter) => iter.next()
         }
     }
 }

src/libcoretest/char.rs

@@ -135,38 +135,35 @@ fn test_escape_default() {
     let s = string('~');
     assert_eq!(s, "~");
     let s = string('\x00');
-    assert_eq!(s, "\\x00");
+    assert_eq!(s, "\\u{0}");
     let s = string('\x1f');
-    assert_eq!(s, "\\x1f");
+    assert_eq!(s, "\\u{1f}");
     let s = string('\x7f');
-    assert_eq!(s, "\\x7f");
-    let s = string('\u00ff');
-    assert_eq!(s, "\\u00ff");
-    let s = string('\u011b');
-    assert_eq!(s, "\\u011b");
-    let s = string('\U0001d4b6');
-    assert_eq!(s, "\\U0001d4b6");
+    assert_eq!(s, "\\u{7f}");
+    let s = string('\u{ff}');
+    assert_eq!(s, "\\u{ff}");
+    let s = string('\u{11b}');
+    assert_eq!(s, "\\u{11b}");
+    let s = string('\u{1d4b6}');
+    assert_eq!(s, "\\u{1d4b6}");
 }
 
 #[test]
 fn test_escape_unicode() {
-    fn string(c: char) -> String {
-        let mut result = String::new();
-        escape_unicode(c, |c| { result.push(c); });
-        return result;
-    }
+    fn string(c: char) -> String { c.escape_unicode().collect() }
+
     let s = string('\x00');
-    assert_eq!(s, "\\x00");
+    assert_eq!(s, "\\u{0}");
     let s = string('\n');
-    assert_eq!(s, "\\x0a");
+    assert_eq!(s, "\\u{a}");
     let s = string(' ');
-    assert_eq!(s, "\\x20");
+    assert_eq!(s, "\\u{20}");
     let s = string('a');
-    assert_eq!(s, "\\x61");
-    let s = string('\u011b');
-    assert_eq!(s, "\\u011b");
-    let s = string('\U0001d4b6');
-    assert_eq!(s, "\\U0001d4b6");
+    assert_eq!(s, "\\u{61}");
+    let s = string('\u{11b}');
+    assert_eq!(s, "\\u{11b}");
+    let s = string('\u{1d4b6}');
+    assert_eq!(s, "\\u{1d4b6}");
 }
 
 #[test]

src/test/compile-fail-fulldeps/macro-crate-cannot-read-embedded-ident.rs

@@ -11,7 +11,7 @@
 // aux-build:macro_crate_test.rs
 // ignore-stage1
 // ignore-android
-// error-pattern: unknown start of token: \x00
+// error-pattern: unknown start of token: \u{0}
 
 // Issue #15750 and #15962 : this test is checking that the standard
 // parser rejects embedded idents.  pnkfelix did not want to attempt