ruff_python_trivia/
whitespace.rs

1use ruff_source_file::LineRanges;
2use ruff_text_size::{TextRange, TextSize};
3
4/// Extract the leading indentation from a line.
5pub fn indentation_at_offset(offset: TextSize, source: &str) -> Option<&str> {
6    let line_start = source.line_start(offset);
7    let indentation = &source[TextRange::new(line_start, offset)];
8
9    indentation
10        .chars()
11        .all(is_python_whitespace)
12        .then_some(indentation)
13}
14
15/// Return `true` if the node starting the given [`TextSize`] has leading content.
16pub fn has_leading_content(offset: TextSize, source: &str) -> bool {
17    let line_start = source.line_start(offset);
18    let leading = &source[TextRange::new(line_start, offset)];
19    leading.chars().any(|char| !is_python_whitespace(char))
20}
21
22/// Return `true` if the node ending at the given [`TextSize`] has trailing content.
23pub fn has_trailing_content(offset: TextSize, source: &str) -> bool {
24    let line_end = source.line_end(offset);
25    let trailing = &source[TextRange::new(offset, line_end)];
26
27    for char in trailing.chars() {
28        if char == '#' {
29            return false;
30        }
31        if !is_python_whitespace(char) {
32            return true;
33        }
34    }
35    false
36}
37
38/// Returns `true` for [whitespace](https://docs.python.org/3/reference/lexical_analysis.html#whitespace-between-tokens)
39/// characters.
40pub const fn is_python_whitespace(c: char) -> bool {
41    matches!(
42        c,
43        // Space, tab, or form-feed
44        ' ' | '\t' | '\x0C'
45    )
46}
47
48/// Extract the leading indentation from a line.
49pub fn leading_indentation(line: &str) -> &str {
50    line.find(|char: char| !is_python_whitespace(char))
51        .map_or(line, |index| &line[..index])
52}
53
54pub trait PythonWhitespace {
55    /// Like `str::trim()`, but only removes whitespace characters that Python considers
56    /// to be [whitespace](https://docs.python.org/3/reference/lexical_analysis.html#whitespace-between-tokens).
57    fn trim_whitespace(&self) -> &Self;
58
59    /// Like `str::trim_start()`, but only removes whitespace characters that Python considers
60    /// to be [whitespace](https://docs.python.org/3/reference/lexical_analysis.html#whitespace-between-tokens).
61    fn trim_whitespace_start(&self) -> &Self;
62
63    /// Like `str::trim_end()`, but only removes whitespace characters that Python considers
64    /// to be [whitespace](https://docs.python.org/3/reference/lexical_analysis.html#whitespace-between-tokens).
65    fn trim_whitespace_end(&self) -> &Self;
66}
67
68impl PythonWhitespace for str {
69    fn trim_whitespace(&self) -> &Self {
70        self.trim_matches(is_python_whitespace)
71    }
72
73    fn trim_whitespace_start(&self) -> &Self {
74        self.trim_start_matches(is_python_whitespace)
75    }
76
77    fn trim_whitespace_end(&self) -> &Self {
78        self.trim_end_matches(is_python_whitespace)
79    }
80}
ruff_python_trivia/whitespace.rs

ruff_python_trivia/
whitespace.rs
