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pub(crate) fn find_words_ascii_space(line: &str) -> impl Iterator<Item = &'_ str> + '_ {
let mut start = 0;
let mut in_whitespace = false;
let mut char_indices = line.char_indices();
std::iter::from_fn(move || {
for (idx, ch) in char_indices.by_ref() {
let next_whitespace = ch == ' ';
if in_whitespace && !next_whitespace {
let word = &line[start..idx];
start = idx;
in_whitespace = next_whitespace;
return Some(word);
}
in_whitespace = next_whitespace;
}
if start < line.len() {
let word = &line[start..];
start = line.len();
return Some(word);
}
None
})
}
#[cfg(test)]
mod tests {
use super::*;
macro_rules! test_find_words {
($ascii_name:ident,
$([ $line:expr, $ascii_words:expr ]),+) => {
#[test]
fn $ascii_name() {
$(
let expected_words: Vec<&str> = $ascii_words.to_vec();
let actual_words = find_words_ascii_space($line)
.collect::<Vec<_>>();
assert_eq!(actual_words, expected_words, "Line: {:?}", $line);
)+
}
};
}
test_find_words!(ascii_space_empty, ["", []]);
test_find_words!(ascii_single_word, ["foo", ["foo"]]);
test_find_words!(ascii_two_words, ["foo bar", ["foo ", "bar"]]);
test_find_words!(
ascii_multiple_words,
["foo bar", ["foo ", "bar"]],
["x y z", ["x ", "y ", "z"]]
);
test_find_words!(ascii_only_whitespace, [" ", [" "]], [" ", [" "]]);
test_find_words!(
ascii_inter_word_whitespace,
["foo bar", ["foo ", "bar"]]
);
test_find_words!(ascii_trailing_whitespace, ["foo ", ["foo "]]);
test_find_words!(ascii_leading_whitespace, [" foo", [" ", "foo"]]);
test_find_words!(
ascii_multi_column_char,
["\u{1f920}", ["\u{1f920}"]] // cowboy emoji ðŸ¤
);
test_find_words!(
ascii_hyphens,
["foo-bar", ["foo-bar"]],
["foo- bar", ["foo- ", "bar"]],
["foo - bar", ["foo ", "- ", "bar"]],
["foo -bar", ["foo ", "-bar"]]
);
test_find_words!(ascii_newline, ["foo\nbar", ["foo\nbar"]]);
test_find_words!(ascii_tab, ["foo\tbar", ["foo\tbar"]]);
test_find_words!(
ascii_non_breaking_space,
["foo\u{00A0}bar", ["foo\u{00A0}bar"]]
);
}