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sane indexing in text

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This commit is contained in:
Aleksey Kladov
2019-07-19 20:55:32 +03:00
parent 8467ba8cdb
commit 0025299370
2 changed files with 13 additions and 11 deletions
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17
crates/ra_syntax/src/syntax_text.rs
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@@ -95,18 +95,21 @@ impl<'a> SyntaxText<'a> {
self.range.is_empty()
}
/// NB, the offsets here are absolute, and this probably doesn't make sense!
pub fn slice(&self, range: impl ops::RangeBounds<TextUnit>) -> SyntaxText<'a> {
let start = match range.start_bound() {
Bound::Included(b) => *b,
Bound::Excluded(b) => *b + TextUnit::from(1u32),
Bound::Unbounded => self.range.start(),
Bound::Included(&b) => b,
Bound::Excluded(_) => panic!("utf-aware slicing can't work this way"),
Bound::Unbounded => 0.into(),
};
let end = match range.end_bound() {
Bound::Included(b) => *b + TextUnit::from(1u32),
Bound::Excluded(b) => *b,
Bound::Unbounded => self.range.end(),
Bound::Included(_) => panic!("utf-aware slicing can't work this way"),
Bound::Excluded(&b) => b,
Bound::Unbounded => self.len(),
};
assert!(start <= end);
let len = end - start;
let start = self.range.start() + start;
let end = start + len;
assert!(
start <= end,
"invalid slice, range: {:?}, slice: {:?}",