wain_syntax_text/
source.rs

1use std::fmt;
2use wain_ast::source::Source;
3
4pub fn describe_position(f: &mut fmt::Formatter<'_>, source: &str, start: usize) -> fmt::Result {
5    if start == source.len() {
6        write!(f, " caused at byte offset {} (end of input)", start)
7    } else {
8        let source = &source[start..];
9        let end = source.find(['\n', '\r'].as_ref()).unwrap_or(source.len());
10        write!(
11            f,
12            " caused at byte offset {}\n\n ... {}\n     ^\n     starts from here",
13            start,
14            &source[..end],
15        )
16    }
17}
18
19#[derive(Clone)]
20pub struct TextSource<'source>(pub(crate) &'source str);
21
22impl<'s> Source for TextSource<'s> {
23    type Raw = &'s str;
24
25    fn describe(&self, f: &mut fmt::Formatter<'_>, offset: usize) -> fmt::Result {
26        describe_position(f, self.0, offset)
27    }
28
29    fn raw(&self) -> Self::Raw {
30        self.0
31    }
32}
wain_syntax_text/source.rs

wain_syntax_text/
source.rs
