Treat ambiguous Modifier_Letters as narrow (unicode-rs#63)

* Treat ambiguous `Modifier_Letter`s as narrow

This matches the behavior of common fonts.

Affects 6 characters:
https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5B%5B%3AEast_Asian_Width%3DAmbiguous%3A%5D-%5B%5B%3AScript%3D%2FLatin%7CGreek%7CCyrillic%2F%3A%5D-%5B%5B%3ABlock%3DNumber+Forms%3A%5D%26%5B%3Asubhead%3DRoman+numerals%3A%5D%5D%5D%5D%26%5B%3AModifier_Letter%3A%5D

* Simplify derivation of ambiguous

Use `Letter` general category instead of script and block.
Changes `ℓ` to narrow, matching common fonts

Author: Jules-Bertholet

scripts/unicode.py

@@ -18,7 +18,6 @@
 # - NormalizationTest.txt (for tests only)
 # - PropList.txt
 # - ReadMe.txt
-# - Scripts.txt
 # - UnicodeData.txt
 # - auxiliary/GraphemeBreakProperty.txt
 # - emoji/emoji-data.txt
@@ -430,22 +429,10 @@ def load_east_asian_widths() -> list[EastAsianWidth]:
             # Catch any leftover codepoints and assign them implicit Neutral/narrow width.
             width_map.append(EastAsianWidth.NARROW)
 
-    # Characters from alphabetic scripts are narrow
-    load_property(
-        "Scripts.txt",
-        r"(?:Latin|Greek|Cyrillic)",
-        lambda cp: (
-            operator.setitem(width_map, cp, EastAsianWidth.NARROW)
-            if width_map[cp] == EastAsianWidth.AMBIGUOUS
-            and not (0x2160 <= cp <= 0x217F)  # Roman numerals remain ambiguous
-            else None
-        ),
-    )
-
-    # Ambiguous `Modifier_Symbol`s are narrow
+    # Ambiguous `Letter`s and `Modifier_Symbol`s are narrow
     load_property(
         "extracted/DerivedGeneralCategory.txt",
-        "Sk",
+        r"(:?Lu|Ll|Lt|Lm|Lo|Sk)",
         lambda cp: (
             operator.setitem(width_map, cp, EastAsianWidth.NARROW)
             if width_map[cp] == EastAsianWidth.AMBIGUOUS

src/lib.rs

@@ -122,8 +122,7 @@
 //!       - Has an [`East_Asian_Width`] of [`Ambiguous`], or
 //!         has a canonical decomposition to an [`Ambiguous`] character followed by [`'\u{0338}'` COMBINING LONG SOLIDUS OVERLAY], or
 //!         is [`'\u{0387}'` GREEK ANO TELEIA](https://util.unicode.org/UnicodeJsps/character.jsp?a=0387), and
-//!       - Does not have a [`General_Category`] of `Modifier_Symbol`, and
-//!       - Does not have a [`Script`] of `Latin`, `Greek`, or `Cyrillic`, or is a Roman numeral in the range `'\u{2160}'..='\u{217F}'`.
+//!       - Does not have a [`General_Category`] of `Letter` or `Modifier_Symbol`.
 //!    7. All other characters have width 1.
 //!
 //! [`'\u{0338}'` COMBINING LONG SOLIDUS OVERLAY]: https://util.unicode.org/UnicodeJsps/character.jsp?a=0338

src/tables.rs

@@ -1022,17 +1022,17 @@ static WIDTH_MIDDLE: Align64<[[u8; 64]; WIDTH_MIDDLE_LEN]> = Align64([
     ],
     #[cfg(feature = "cjk")]
     [
-        0x00, 0x9D, 0x02, 0x02, 0x02, 0x9E, 0x9F, 0xA0, 0x02, 0x04, 0x02, 0x05, 0x06, 0x07, 0x08,
+        0x00, 0x9D, 0x02, 0x02, 0x02, 0x02, 0x9E, 0x9F, 0x02, 0x04, 0x02, 0x05, 0x06, 0x07, 0x08,
         0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
         0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x02, 0x02, 0x1E, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
         0x02, 0x1F, 0x20, 0x21, 0x22, 0x23, 0x02, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x02, 0x2A,
         0x02, 0x02, 0x02, 0x02,
     ],
     #[cfg(feature = "cjk")]
     [
-        0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0x2E, 0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE,
-        0x33, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0xAF, 0x02, 0x02, 0x35, 0x36, 0x37, 0x02, 0x38,
-        0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0xB0, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39,
+        0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0x2E, 0xA7, 0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD,
+        0x33, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0xAE, 0x02, 0x02, 0x35, 0x36, 0x37, 0x02, 0x38,
+        0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0xAF, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39,
         0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39,
         0x39, 0x39, 0x39, 0x39,
     ],
@@ -1042,23 +1042,23 @@ static WIDTH_MIDDLE: Align64<[[u8; 64]; WIDTH_MIDDLE_LEN]> = Align64([
         0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39,
         0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39,
         0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x4C, 0x02, 0x02, 0x02, 0x02, 0x02,
-        0xB1, 0x4E, 0x4F, 0xB2,
+        0xB0, 0x4E, 0x4F, 0xB1,
     ],
     #[cfg(feature = "cjk")]
     [
         0x85, 0x86, 0x75, 0x02, 0x02, 0x87, 0x02, 0x02, 0x02, 0x88, 0x02, 0x02, 0x02, 0x02, 0x02,
         0x02, 0x02, 0x89, 0x8A, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
-        0x02, 0x02, 0x8B, 0x8C, 0xB3, 0xB4, 0x8E, 0x02, 0x8F, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95,
+        0x02, 0x02, 0x8B, 0x8C, 0xB2, 0xB3, 0x8E, 0x02, 0x8F, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95,
         0x96, 0x02, 0x97, 0x02, 0x02, 0x98, 0x99, 0x9A, 0x9B, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
         0x02, 0x02, 0x02, 0x02,
     ],
 ]);
 
 #[cfg(feature = "cjk")]
-const WIDTH_LEAVES_LEN: usize = 181;
+const WIDTH_LEAVES_LEN: usize = 180;
 #[cfg(not(feature = "cjk"))]
 const WIDTH_LEAVES_LEN: usize = 157;
-/// Autogenerated. 181 sub-table(s). Consult [`lookup_width`] for layout info.
+/// Autogenerated. 180 sub-table(s). Consult [`lookup_width`] for layout info.
 static WIDTH_LEAVES: Align32<[[u8; 32]; WIDTH_LEAVES_LEN]> = Align32([
     [
         0x55, 0x55, 0x75, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
@@ -1852,12 +1852,6 @@ static WIDTH_LEAVES: Align32<[[u8; 32]; WIDTH_LEAVES_LEN]> = Align32([
         0x55, 0x55,
     ],
     #[cfg(feature = "cjk")]
-    [
-        0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-        0x55, 0x55, 0x95, 0xA9, 0x59, 0x56, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-        0x55, 0x55,
-    ],
-    #[cfg(feature = "cjk")]
     [
         0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03,
         0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x55, 0x55,
@@ -1883,7 +1877,7 @@ static WIDTH_LEAVES: Align32<[[u8; 32]; WIDTH_LEAVES_LEN]> = Align32([
     ],
     #[cfg(feature = "cjk")]
     [
-        0x95, 0x59, 0x59, 0x55, 0x95, 0x65, 0x55, 0x55, 0x69, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
+        0x95, 0x59, 0x59, 0x55, 0x55, 0x65, 0x55, 0x55, 0x69, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
         0x55, 0x55, 0x55, 0x55, 0x55, 0x95, 0x56, 0x95, 0x6A, 0xAA, 0xAA, 0xAA, 0x55, 0xAA, 0xAA,
         0x5A, 0x55,
     ],

tests/tests.rs

@@ -78,6 +78,14 @@ fn test_default_ignorable() {
     assert_width!('\u{E0000}', Some(0), Some(0));
 }
 
+#[test]
+fn test_ambiguous() {
+    assert_width!("\u{B7}", 1, 2);
+    assert_width!("\u{0387}", 1, 2);
+    assert_width!("\u{A8}", 1, 1);
+    assert_width!("\u{02C9}", 1, 1);
+}
+
 #[test]
 fn test_jamo() {
     assert_width!('\u{1100}', Some(2), Some(2));