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|
//! Utility functions to categorize a `char`.
use crate::LineEnding;
#[derive(Debug, Eq, PartialEq)]
pub enum CharCategory {
Whitespace,
Eol,
Word,
Punctuation,
Unknown,
}
#[inline]
pub fn categorize_char(ch: char) -> CharCategory {
if char_is_line_ending(ch) {
CharCategory::Eol
} else if ch.is_whitespace() {
CharCategory::Whitespace
} else if char_is_word(ch) {
CharCategory::Word
} else if char_is_punctuation(ch) {
CharCategory::Punctuation
} else {
CharCategory::Unknown
}
}
/// Determine whether a character is a line ending.
#[inline]
pub fn char_is_line_ending(ch: char) -> bool {
LineEnding::from_char(ch).is_some()
}
/// Determine whether a character qualifies as (non-line-break)
/// whitespace.
#[inline]
pub fn char_is_whitespace(ch: char) -> bool {
// TODO: this is a naive binary categorization of whitespace
// characters. For display, word wrapping, etc. we'll need a better
// categorization based on e.g. breaking vs non-breaking spaces
// and whether they're zero-width or not.
match ch {
//'\u{1680}' | // Ogham Space Mark (here for completeness, but usually displayed as a dash, not as whitespace)
'\u{0009}' | // Character Tabulation
'\u{0020}' | // Space
'\u{00A0}' | // No-break Space
'\u{180E}' | // Mongolian Vowel Separator
'\u{202F}' | // Narrow No-break Space
'\u{205F}' | // Medium Mathematical Space
'\u{3000}' | // Ideographic Space
'\u{FEFF}' // Zero Width No-break Space
=> true,
// En Quad, Em Quad, En Space, Em Space, Three-per-em Space,
// Four-per-em Space, Six-per-em Space, Figure Space,
// Punctuation Space, Thin Space, Hair Space, Zero Width Space.
ch if ('\u{2000}' ..= '\u{200B}').contains(&ch) => true,
_ => false,
}
}
#[inline]
pub fn char_is_punctuation(ch: char) -> bool {
use unicode_general_category::{get_general_category, GeneralCategory};
matches!(
get_general_category(ch),
GeneralCategory::OtherPunctuation
| GeneralCategory::OpenPunctuation
| GeneralCategory::ClosePunctuation
| GeneralCategory::InitialPunctuation
| GeneralCategory::FinalPunctuation
| GeneralCategory::ConnectorPunctuation
| GeneralCategory::DashPunctuation
| GeneralCategory::MathSymbol
| GeneralCategory::CurrencySymbol
| GeneralCategory::ModifierSymbol
)
}
#[inline]
pub fn char_is_word(ch: char) -> bool {
ch.is_alphanumeric() || ch == '_'
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_categorize() {
const EOL_TEST_CASE: &str = "\n\r\u{000B}\u{000C}\u{0085}\u{2028}\u{2029}";
const WORD_TEST_CASE: &str = "_hello_world_あいうえおー1234567890１２３４５６７８９０";
const PUNCTUATION_TEST_CASE: &str =
"!\"#$%&\'()*+,-./:;<=>?@[\\]^`{|}~！”＃＄％＆’（）＊＋、。：；＜＝＞？＠「」＾｀｛｜｝～";
const WHITESPACE_TEST_CASE: &str = " ";
for ch in EOL_TEST_CASE.chars() {
assert_eq!(CharCategory::Eol, categorize_char(ch));
}
for ch in WHITESPACE_TEST_CASE.chars() {
assert_eq!(
CharCategory::Whitespace,
categorize_char(ch),
"Testing '{}', but got `{:?}` instead of `Category::Whitespace`",
ch,
categorize_char(ch)
);
}
for ch in WORD_TEST_CASE.chars() {
assert_eq!(
CharCategory::Word,
categorize_char(ch),
"Testing '{}', but got `{:?}` instead of `Category::Word`",
ch,
categorize_char(ch)
);
}
for ch in PUNCTUATION_TEST_CASE.chars() {
assert_eq!(
CharCategory::Punctuation,
categorize_char(ch),
"Testing '{}', but got `{:?}` instead of `Category::Punctuation`",
ch,
categorize_char(ch)
);
}
}
}
|
