egglog_ast/
span.rs

1use std::fmt::{self, Debug, Display};
2use std::sync::Arc;
3
4#[derive(Clone, PartialEq, Eq, Hash)]
5pub enum Span {
6    Panic,
7    Egglog(Arc<EgglogSpan>),
8    Rust(Arc<RustSpan>),
9}
10
11#[derive(Debug, Clone, PartialEq, Eq, Hash)]
12pub struct EgglogSpan {
13    pub file: Arc<SrcFile>,
14    pub i: usize,
15    pub j: usize,
16}
17
18#[derive(Debug, Clone, PartialEq, Eq, Hash)]
19pub struct RustSpan {
20    pub file: &'static str,
21    pub line: u32,
22    pub column: u32,
23}
24
25#[derive(Debug, PartialEq, Eq, Hash, Clone)]
26pub struct SrcFile {
27    pub name: Option<String>,
28    pub contents: String,
29}
30
31impl SrcFile {
32    pub fn get_location(&self, offset: usize) -> (usize, usize) {
33        let mut line = 1;
34        let mut col = 1;
35        for (i, c) in self.contents.char_indices() {
36            if i == offset {
37                break;
38            }
39            if c == '\n' {
40                line += 1;
41                col = 1;
42            } else {
43                col += 1;
44            }
45        }
46        (line, col)
47    }
48}
49
50impl Span {
51    pub fn string(&self) -> &str {
52        match self {
53            Span::Panic => panic!("Span::Panic in Span::string"),
54            Span::Rust(_) => panic!("Span::Rust cannot track end position"),
55            Span::Egglog(span) => &span.file.contents[span.i..span.j],
56        }
57    }
58}
59
60impl Debug for Span {
61    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
62        write!(f, "{self}")
63    }
64}
65
66impl Display for Span {
67    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
68        match self {
69            Span::Panic => panic!("Span::Panic in impl Display"),
70            Span::Rust(span) => write!(f, "At {}:{} of {}", span.line, span.column, span.file),
71            Span::Egglog(span) => {
72                let (start_line, start_col) = span.file.get_location(span.i);
73                let (end_line, end_col) = span
74                    .file
75                    .get_location((span.j.saturating_sub(1)).max(span.i));
76                let quote = self.string();
77                match (&span.file.name, start_line == end_line) {
78                    (Some(filename), true) => write!(
79                        f,
80                        "In {start_line}:{start_col}-{end_col} of {filename}: {quote}"
81                    ),
82                    (Some(filename), false) => write!(
83                        f,
84                        "In {start_line}:{start_col}-{end_line}:{end_col} of {filename}: {quote}"
85                    ),
86                    (None, false) => write!(
87                        f,
88                        "In {start_line}:{start_col}-{end_line}:{end_col}: {quote}"
89                    ),
90                    (None, true) => {
91                        write!(f, "In {start_line}:{start_col}-{end_col}: {quote}")
92                    }
93                }
94            }
95        }
96    }
97}
98
99#[cfg(test)]
100mod tests {
101    use super::*;
102
103    #[test]
104    fn egglog_span_display_preserves_full_path() {
105        let path = "/tmp/egglog/full/path/example.egg".to_string();
106        let span = Span::Egglog(Arc::new(EgglogSpan {
107            file: Arc::new(SrcFile {
108                name: Some(path.clone()),
109                contents: "(bad)".to_string(),
110            }),
111            i: 0,
112            j: 5,
113        }));
114
115        assert_eq!(span.to_string(), format!("In 1:1-5 of {path}: (bad)"));
116    }
117}
egglog_ast/span.rs

egglog_ast/
span.rs
