clap_builder/output/textwrap/
word_separators.rs

1pub(crate) fn find_words_ascii_space(line: &str) -> impl Iterator<Item = &'_ str> + '_ {
2    let mut start = 0;
3    let mut in_whitespace = false;
4    let mut char_indices = line.char_indices();
5
6    std::iter::from_fn(move || {
7        for (idx, ch) in char_indices.by_ref() {
8            let next_whitespace = ch == ' ';
9            if in_whitespace && !next_whitespace {
10                let word = &line[start..idx];
11                start = idx;
12                in_whitespace = next_whitespace;
13                return Some(word);
14            }
15
16            in_whitespace = next_whitespace;
17        }
18
19        if start < line.len() {
20            let word = &line[start..];
21            start = line.len();
22            return Some(word);
23        }
24
25        None
26    })
27}
28
29#[cfg(test)]
30mod tests {
31    use super::*;
32
33    macro_rules! test_find_words {
34        ($ascii_name:ident,
35         $([ $line:expr, $ascii_words:expr ]),+) => {
36            #[test]
37            fn $ascii_name() {
38                $(
39                    let expected_words: Vec<&str> = $ascii_words.to_vec();
40                    let actual_words = find_words_ascii_space($line)
41                        .collect::<Vec<_>>();
42                    assert_eq!(actual_words, expected_words, "Line: {:?}", $line);
43                )+
44            }
45        };
46    }
47
48    test_find_words!(ascii_space_empty, ["", []]);
49
50    test_find_words!(ascii_single_word, ["foo", ["foo"]]);
51
52    test_find_words!(ascii_two_words, ["foo bar", ["foo ", "bar"]]);
53
54    test_find_words!(
55        ascii_multiple_words,
56        ["foo bar", ["foo ", "bar"]],
57        ["x y z", ["x ", "y ", "z"]]
58    );
59
60    test_find_words!(ascii_only_whitespace, [" ", [" "]], ["    ", ["    "]]);
61
62    test_find_words!(
63        ascii_inter_word_whitespace,
64        ["foo   bar", ["foo   ", "bar"]]
65    );
66
67    test_find_words!(ascii_trailing_whitespace, ["foo   ", ["foo   "]]);
68
69    test_find_words!(ascii_leading_whitespace, ["   foo", ["   ", "foo"]]);
70
71    test_find_words!(
72        ascii_multi_column_char,
73        ["\u{1f920}", ["\u{1f920}"]] // cowboy emoji 🤠
74    );
75
76    test_find_words!(
77        ascii_hyphens,
78        ["foo-bar", ["foo-bar"]],
79        ["foo- bar", ["foo- ", "bar"]],
80        ["foo - bar", ["foo ", "- ", "bar"]],
81        ["foo -bar", ["foo ", "-bar"]]
82    );
83
84    test_find_words!(ascii_newline, ["foo\nbar", ["foo\nbar"]]);
85
86    test_find_words!(ascii_tab, ["foo\tbar", ["foo\tbar"]]);
87
88    test_find_words!(
89        ascii_non_breaking_space,
90        ["foo\u{00A0}bar", ["foo\u{00A0}bar"]]
91    );
92}
clap_builder/output/textwrap/word_separators.rs

clap_builder/output/textwrap/
word_separators.rs
