Auto merge of #49283 - varkor:combining-chars-escape_debug, r=SimonSapin

Escape combining characters in char::Debug Although combining characters are technically printable, they make little sense to print on their own with `Debug`: it'd be better to escape them like non-printable characters. This is a breaking change, but I imagine the fact `escape_debug` is rare and almost certainly primarily used for debugging that this is an acceptable change. Resolves #41922. r? @alexcrichton cc @clarcharr
rust-lang · May 21, 2018 · 65a16c0 · 65a16c0
2 parents cb20f68 + b653937
commit 65a16c0
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Showing 7 changed files with 197 additions and 33 deletions.
diff --git a/.gitignore b/.gitignore
@@ -74,13 +74,13 @@ __pycache__/
 /obj/
 /rt/
 /rustllvm/
-/src/libstd_unicode/DerivedCoreProperties.txt
-/src/libstd_unicode/DerivedNormalizationProps.txt
-/src/libstd_unicode/PropList.txt
-/src/libstd_unicode/ReadMe.txt
-/src/libstd_unicode/Scripts.txt
-/src/libstd_unicode/SpecialCasing.txt
-/src/libstd_unicode/UnicodeData.txt
+/src/libcore/unicode/DerivedCoreProperties.txt
+/src/libcore/unicode/DerivedNormalizationProps.txt
+/src/libcore/unicode/PropList.txt
+/src/libcore/unicode/ReadMe.txt
+/src/libcore/unicode/Scripts.txt
+/src/libcore/unicode/SpecialCasing.txt
+/src/libcore/unicode/UnicodeData.txt
 /stage[0-9]+/
 /target
 target/

diff --git a/src/liballoc/str.rs b/src/liballoc/str.rs
@@ -372,12 +372,21 @@ impl str {
 
     /// Escapes each char in `s` with [`char::escape_debug`].
     ///
+    /// Note: only extended grapheme codepoints that begin the string will be
+    /// escaped.
+    ///
     /// [`char::escape_debug`]: primitive.char.html#method.escape_debug
     #[unstable(feature = "str_escape",
                reason = "return type may change to be an iterator",
                issue = "27791")]
     pub fn escape_debug(&self) -> String {
-        self.chars().flat_map(|c| c.escape_debug()).collect()
+        let mut string = String::with_capacity(self.len());
+        let mut chars = self.chars();
+        if let Some(first) = chars.next() {
+            string.extend(first.escape_debug_ext(true))
+        }
+        string.extend(chars.flat_map(|c| c.escape_debug_ext(false)));
+        string
     }
 
     /// Escapes each char in `s` with [`char::escape_default`].

diff --git a/src/liballoc/tests/str.rs b/src/liballoc/tests/str.rs
@@ -989,6 +989,12 @@ fn test_escape_unicode() {
 
 #[test]
 fn test_escape_debug() {
+    // Note that there are subtleties with the number of backslashes
+    // on the left- and right-hand sides. In particular, Unicode code points
+    // are usually escaped with two backslashes on the right-hand side, as
+    // they are escaped. However, when the character is unescaped (e.g. for
+    // printable characters), only a single backslash appears (as the character
+    // itself appears in the debug string).
     assert_eq!("abc".escape_debug(), "abc");
     assert_eq!("a c".escape_debug(), "a c");
     assert_eq!("éèê".escape_debug(), "éèê");
@@ -999,6 +1005,7 @@ fn test_escape_debug() {
     assert_eq!("\u{10000}\u{10ffff}".escape_debug(), "\u{10000}\\u{10ffff}");
     assert_eq!("ab\u{200b}".escape_debug(), "ab\\u{200b}");
     assert_eq!("\u{10d4ea}\r".escape_debug(), "\\u{10d4ea}\\r");
+    assert_eq!("\u{301}a\u{301}bé\u{e000}".escape_debug(), "\\u{301}a\u{301}bé\\u{e000}");
 }
 
 #[test]

diff --git a/src/libcore/char/methods.rs b/src/libcore/char/methods.rs
@@ -187,6 +187,27 @@ impl char {
         }
     }
 
+    /// An extended version of `escape_debug` that optionally permits escaping
+    /// Extended Grapheme codepoints. This allows us to format characters like
+    /// nonspacing marks better when they're at the start of a string.
+    #[doc(hidden)]
+    #[unstable(feature = "str_internals", issue = "0")]
+    #[inline]
+    pub fn escape_debug_ext(self, escape_grapheme_extended: bool) -> EscapeDebug {
+        let init_state = match self {
+            '\t' => EscapeDefaultState::Backslash('t'),
+            '\r' => EscapeDefaultState::Backslash('r'),
+            '\n' => EscapeDefaultState::Backslash('n'),
+            '\\' | '\'' | '"' => EscapeDefaultState::Backslash(self),
+            _ if escape_grapheme_extended && self.is_grapheme_extended() => {
+                EscapeDefaultState::Unicode(self.escape_unicode())
+            }
+            _ if is_printable(self) => EscapeDefaultState::Char(self),
+            _ => EscapeDefaultState::Unicode(self.escape_unicode()),
+        };
+        EscapeDebug(EscapeDefault { state: init_state })
+    }
+
     /// Returns an iterator that yields the literal escape code of a character
     /// as `char`s.
     ///
@@ -224,15 +245,7 @@ impl char {
     #[stable(feature = "char_escape_debug", since = "1.20.0")]
     #[inline]
     pub fn escape_debug(self) -> EscapeDebug {
-        let init_state = match self {
-            '\t' => EscapeDefaultState::Backslash('t'),
-            '\r' => EscapeDefaultState::Backslash('r'),
-            '\n' => EscapeDefaultState::Backslash('n'),
-            '\\' | '\'' | '"' => EscapeDefaultState::Backslash(self),
-            c if is_printable(c) => EscapeDefaultState::Char(c),
-            c => EscapeDefaultState::Unicode(c.escape_unicode()),
-        };
-        EscapeDebug(EscapeDefault { state: init_state })
+        self.escape_debug_ext(true)
     }
 
     /// Returns an iterator that yields the literal escape code of a character
@@ -692,6 +705,15 @@ impl char {
         general_category::Cc(self)
     }
 
+    /// Returns true if this `char` is an extended grapheme character, and false otherwise.
+    ///
+    /// 'Extended grapheme character' is defined in terms of the Unicode Shaping and Rendering
+    /// Category `Grapheme_Extend`.
+    #[inline]
+    pub(crate) fn is_grapheme_extended(self) -> bool {
+        derived_property::Grapheme_Extend(self)
+    }
+
     /// Returns true if this `char` is numeric, and false otherwise.
     ///
     /// 'Numeric'-ness is defined in terms of the Unicode General Categories

diff --git a/src/libcore/tests/char.rs b/src/libcore/tests/char.rs
@@ -181,6 +181,7 @@ fn test_escape_debug() {
     assert_eq!(string('\u{ff}'), "\u{ff}");
     assert_eq!(string('\u{11b}'), "\u{11b}");
     assert_eq!(string('\u{1d4b6}'), "\u{1d4b6}");
+    assert_eq!(string('\u{301}'), "\\u{301}");     // combining character
     assert_eq!(string('\u{200b}'),"\\u{200b}");      // zero width space
     assert_eq!(string('\u{e000}'), "\\u{e000}");     // private use 1
     assert_eq!(string('\u{100000}'), "\\u{100000}"); // private use 2

diff --git a/src/libcore/unicode/tables.rs b/src/libcore/unicode/tables.rs
@@ -1,4 +1,4 @@
-// Copyright 2012-2016 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2012-2018 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
@@ -549,6 +549,127 @@ pub mod derived_property {
         Cased_table.lookup(c)
     }
 
+    pub const Grapheme_Extend_table: &super::BoolTrie = &super::BoolTrie {
+        r1: [
+            0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
+            0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
+            0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
+            0xffffffffffffffff, 0x0000ffffffffffff, 0x0000000000000000, 0x0000000000000000,
+            0x0000000000000000, 0x0000000000000000, 0x00000000000003f8, 0x0000000000000000,
+            0x0000000000000000, 0x0000000000000000, 0xbffffffffffe0000, 0x00000000000000b6,
+            0x0000000007ff0000, 0x00010000fffff800, 0x0000000000000000, 0x00003d9f9fc00000,
+            0xffff000000020000, 0x00000000000007ff, 0x0001ffc000000000, 0x000ff80000000000
+        ],
+        r2: [
+            0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 8, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 7, 2, 20, 21,
+            22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 32, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 33, 34, 35, 36, 37, 2, 38, 2, 39, 2, 2, 2, 40, 41, 42, 2, 43,
+            44, 45, 46, 47, 2, 2, 48, 2, 2, 2, 49, 2, 2, 2, 2, 2, 2, 2, 2, 50, 2, 2, 51, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 52, 2, 53, 2, 54, 2, 2, 2, 2, 2, 2, 2, 2, 55,
+            2, 56, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 57, 58, 59, 2, 2, 2, 2, 60, 2, 2, 61, 62, 63, 64, 65, 66, 67,
+            68, 69, 2, 2, 2, 70, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 71, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 72, 2, 2, 2, 2, 2, 58, 2
+        ],
+        r3: &[
+            0x00003eeffbc00000, 0x000000000e000000, 0x0000000000000000, 0xfffffffbfff00000,
+            0x1400000000000007, 0x0000000c00fe21fe, 0x5000000000000002, 0x0000000c0080201e,
+            0x1000000000000006, 0x0023000000023986, 0xfc00000c000021be, 0xd000000000000002,
+            0x0000000c00c0201e, 0x4000000000000004, 0x0000000000802001, 0xc000000000000001,
+            0x0000000c00603dc1, 0x9000000000000002, 0x0000000c00603044, 0x5800000000000003,
+            0x00000000805c8400, 0x07f2000000000000, 0x0000000000007f80, 0x1bf2000000000000,
+            0x0000000000003f00, 0x02a0000003000000, 0x7ffe000000000000, 0x1ffffffffeffe0df,
+            0x0000000000000040, 0x66fde00000000000, 0x001e0001c3000000, 0x0000000020002064,
+            0x00000000e0000000, 0x001c0000001c0000, 0x000c0000000c0000, 0x3fb0000000000000,
+            0x00000000200ffe40, 0x0000000000003800, 0x0000020000000060, 0x0e04018700000000,
+            0x0000000009800000, 0x9ff81fe57f400000, 0x7fff000000000000, 0x17d000000000000f,
+            0x000ff80000000004, 0x00003b3c00000003, 0x0003a34000000000, 0x00cff00000000000,
+            0x031021fdfff70000, 0xfbffffffffffffff, 0x0000000000001000, 0x0001ffffffff0000,
+            0x0003800000000000, 0x8000000000000000, 0xffffffff00000000, 0x0000fc0000000000,
+            0x0000000006000000, 0x3ff7800000000000, 0x00000000c0000000, 0x0003000000000000,
+            0x0000006000000844, 0x0003ffff00000030, 0x00003fc000000000, 0x000000000003ff80,
+            0x13c8000000000007, 0x0000002000000000, 0x00667e0000000000, 0x1000000000001008,
+            0xc19d000000000000, 0x0040300000000002, 0x0000212000000000, 0x0000000040000000,
+            0x0000ffff0000ffff
+        ],
+        r4: [
+            0, 1, 2, 2, 2, 2, 3, 2, 2, 2, 2, 4, 2, 5, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 7, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2
+        ],
+        r5: &[
+            0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 6, 7, 8, 0, 9, 10, 11, 12, 13, 0, 0, 14, 15, 16, 0, 0, 17, 18, 19, 20,
+            0, 0, 21, 22, 23, 24, 25, 0, 26, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 27, 28, 29, 0, 0, 0,
+            0, 0, 30, 0, 31, 0, 32, 33, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 34, 35, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            36, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 37, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 38, 39, 0, 0, 40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 41, 42, 43, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 44, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 45, 0, 46, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 47, 48, 0, 0, 48, 48,
+            48, 49, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+        ],
+        r6: &[
+            0x0000000000000000, 0x2000000000000000, 0x0000000100000000, 0x07c0000000000000,
+            0x870000000000f06e, 0x0000006000000000, 0xff00000000000002, 0x800000000000007f,
+            0x0678000000000003, 0x001fef8000000007, 0x0008000000000000, 0x7fc0000000000003,
+            0x0000000000001c00, 0x40d3800000000000, 0x000007f880000000, 0x5000000000000003,
+            0x001f1fc000800001, 0xff00000000000000, 0x000000000000005c, 0xa5f9000000000000,
+            0x000000000000000d, 0xb03c800000000000, 0x0000000030000001, 0xa7f8000000000000,
+            0x0000000000000001, 0x00bf280000000000, 0x00000fbce0000000, 0x79f800000000067e,
+            0x000000000e7e0080, 0x00000000037ffc00, 0xbf7f000000000000, 0x006dfcfffffc0000,
+            0xb47e000000000000, 0x00000000000000bf, 0x001f000000000000, 0x007f000000000000,
+            0x0000000000078000, 0x0000000060000000, 0xf807c3a000000000, 0x00003c0000000fe7,
+            0x000000000000001c, 0xf87fffffffffffff, 0x00201fffffffffff, 0x0000fffef8000010,
+            0x000007dbf9ffff7f, 0x00000000007f0000, 0x00000000000007f0, 0xffffffff00000000,
+            0xffffffffffffffff, 0x0000ffffffffffff
+        ],
+    };
+
+    pub fn Grapheme_Extend(c: char) -> bool {
+        Grapheme_Extend_table.lookup(c)
+    }
+
     pub const Lowercase_table: &super::BoolTrie = &super::BoolTrie {
         r1: [
             0x0000000000000000, 0x07fffffe00000000, 0x0420040000000000, 0xff7fffff80000000,