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}
93