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Lisu tone letters #48

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merged 2 commits into from
May 21, 2024
Merged

Lisu tone letters #48

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ded852c
Revert "Test width = sum(grapheme cluster widths)"
Jules-Bertholet May 13, 2024
b3ab633
Support Lisu tone letters
Jules-Bertholet May 13, 2024
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3 changes: 1 addition & 2 deletions scripts/unicode.py
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Original file line number Diff line number Diff line change
Expand Up @@ -754,9 +754,8 @@ def main(module_path: str):
{EffectiveWidth.NARROW, EffectiveWidth.AMBIGUOUS},
)

# Download files for use by tests
# Download normalization test file for use by tests
fetch_open("NormalizationTest.txt", "../tests/")
fetch_open("auxiliary/GraphemeBreakTest.txt", "../tests/")

print("------------------------")
total_size = 0
Expand Down
78 changes: 38 additions & 40 deletions src/lib.rs
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Expand Up @@ -30,17 +30,18 @@
//! # Rules for determining width
//!
//! This crate currently uses the following rules to determine the width of a
//! character or string, in order of decreasing precedence. These may be tweaked in the future;
//! however see [guarantees](#guarantees) below.
//! character or string, in order of decreasing precedence. These may be tweaked in the future.
//!
//! 1. [Emoji presentation sequences] have width 2.
//! 2. Outside of an East Asian context, [text presentation sequences] have width 1
//! if their base character:
//! - Has the [`Emoji_Presentation`] property, and
//! - Is not in the [Enclosed Ideographic Supplement] block.
//! 3. The sequence `"\r\n"` has width 1.
//! 4. [`'\u{115F}'` HANGUL CHOSEONG FILLER](https://util.unicode.org/UnicodeJsps/character.jsp?a=115F) has width 2.
//! 5. The following have width 0:
//! 4. [Lisu tone letter] combinations consisting of a character in the range `'\u{A4F8}'..='\u{A4FB}'`
//! followed by a character in the range `'\u{A4FC}'..='\u{A4FD}'` have width 1.
//! 5. [`'\u{115F}'` HANGUL CHOSEONG FILLER](https://util.unicode.org/UnicodeJsps/character.jsp?a=115F) has width 2.
//! 6. The following have width 0:
//! - [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BDefault_Ignorable_Code_Point%7D)
//! with the [`Default_Ignorable_Code_Point`] property.
//! - [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BGrapheme_Extend%7D)
Expand All @@ -56,11 +57,11 @@
//! - [`'\u{1B43}'` BALINESE VOWEL SIGN PEPET TEDUNG](https://util.unicode.org/UnicodeJsps/character.jsp?a=1B43).
//! - [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BHangul_Syllable_Type%3DV%7D%5Cp%7BHangul_Syllable_Type%3DT%7D)
//! with a [`Hangul_Syllable_Type`] of `Vowel_Jamo` (`V`) or `Trailing_Jamo` (`T`).
//! 6. [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BEast_Asian_Width%3DF%7D%5Cp%7BEast_Asian_Width%3DW%7D)
//! 7. [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BEast_Asian_Width%3DF%7D%5Cp%7BEast_Asian_Width%3DW%7D)
//! with an [`East_Asian_Width`] of [`Fullwidth`] or [`Wide`] have width 2.
//! 7. [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BEast_Asian_Width%3DA%7D)
//! 8. [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BEast_Asian_Width%3DA%7D)
//! with an [`East_Asian_Width`] of [`Ambiguous`] have width 2 in an East Asian context, and width 1 otherwise.
//! 8. All other characters have width 1.
//! 9. All other characters have width 1.
//!
//! [`Default_Ignorable_Code_Point`]: https://www.unicode.org/versions/Unicode15.0.0/ch05.pdf#G40095
//! [`East_Asian_Width`]: https://www.unicode.org/reports/tr11/#ED1
Expand All @@ -77,16 +78,12 @@
//!
//! [Enclosed Ideographic Supplement]: https://unicode.org/charts/PDF/U1F200.pdf
//!
//! ## Guarantees
//! [Lisu tone letter]: https://www.unicode.org/versions/Unicode15.0.0/ch18.pdf#G42078
//!
//! - Any two canonically equivalent strings have the same non-CJK width.
//! This will not change in any future semver-compatible version.
//! (This guarantee does not currently hold for the CJK width variants.)
//! - The width of any string equals the sum of the widths of its [extended grapheme clusters].
//! This is unlikely to change in any future semver-compatible version.
//! (This guarantee holds for both CJK and non-CJK width.)
//! ## Canonical equivalence
//!
//! [extended grapheme clusters]: https://www.unicode.org/reports/tr29/#Grapheme_Cluster_Boundaries
//! The non-CJK width methods guarantee that canonically equivalent strings are assigned the same width.
//! However, this guarantee does not currently hold for the CJK width variants.

#![forbid(unsafe_code)]
#![deny(missing_docs)]
Expand All @@ -102,14 +99,6 @@ pub use tables::UNICODE_VERSION;
mod tables;

/// Methods for determining displayed width of Unicode characters.
///
/// **NB:** the width of a string may differ from the sum of the widths of its characters;
/// see the [crate-level documentation](crate#rules-for-determining-width) for more.
/// Instead of working with individual characters, consider using [extended grapheme clusters],
/// perhaps with the [`unicode-segmentation`] crate.
///
/// [extended grapheme clusters]: https://www.unicode.org/reports/tr29/#Grapheme_Cluster_Boundaries
/// [`unicode-segmentation`]: https://docs.rs/unicode-segmentation/latest/unicode_segmentation/trait.UnicodeSegmentation.html#tymethod.graphemes
pub trait UnicodeWidthChar {
/// Returns the character's displayed width in columns, or `None` if the
/// character is a control character.
Expand Down Expand Up @@ -200,8 +189,14 @@ impl UnicodeWidthStr for str {
enum NextCharInfo {
#[default]
Default,
/// `'\n'`
LineFeed = 0x0A,
/// `'\u{A4FC}'..='\u{A4FD}'`
/// <https://www.unicode.org/versions/Unicode15.0.0/ch18.pdf#G42078>
TrailingLisuToneLetter,
/// `'\u{FE0E}'`
Vs15 = 0x0E,
/// `'\u{FE0F}'`
Vs16 = 0x0F,
}

Expand All @@ -219,25 +214,28 @@ fn str_width(s: &str, is_cjk: bool) -> usize {
/// they're treated as single width.
#[inline]
fn width_in_str(c: char, is_cjk: bool, next_info: NextCharInfo) -> (usize, NextCharInfo) {
match next_info {
NextCharInfo::Vs15 if !is_cjk && cw::starts_non_ideographic_text_presentation_seq(c) => {
(1, NextCharInfo::Default)
if next_info == NextCharInfo::Vs16 && cw::starts_emoji_presentation_seq(c) {
(2, NextCharInfo::Default)
} else if c <= '\u{A0}' {
match c {
'\n' => (1, NextCharInfo::LineFeed),
'\r' if next_info == NextCharInfo::LineFeed => (0, NextCharInfo::Default),
_ => (1, NextCharInfo::Default),
}
NextCharInfo::Vs16 if cw::starts_emoji_presentation_seq(c) => (2, NextCharInfo::Default),
_ => {
if c <= '\u{A0}' {
match c {
'\n' => (1, NextCharInfo::LineFeed),
'\r' if next_info == NextCharInfo::LineFeed => (0, NextCharInfo::Default),
_ => (1, NextCharInfo::Default),
}
} else {
match c {
'\u{FE0E}' => (0, NextCharInfo::Vs15),
'\u{FE0F}' => (0, NextCharInfo::Vs16),
_ => (cw::lookup_width(c, is_cjk), NextCharInfo::Default),
}
} else {
match (c, next_info) {
('\u{A4F8}'..='\u{A4FB}', NextCharInfo::TrailingLisuToneLetter) => {
(0, NextCharInfo::Default)
}
('\u{A4FC}'..='\u{A4FD}', _) => (1, NextCharInfo::TrailingLisuToneLetter),
('\u{FE0E}', _) => (0, NextCharInfo::Vs15),
('\u{FE0F}', _) => (0, NextCharInfo::Vs16),
(_, NextCharInfo::Vs15)
if !is_cjk && cw::starts_non_ideographic_text_presentation_seq(c) =>
{
(1, NextCharInfo::Default)
}
_ => (cw::lookup_width(c, is_cjk), NextCharInfo::Default),
}
}
}
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