cynic_parser/
span.rs

1#[derive(Debug, PartialEq, Eq, Clone, Copy, Default)]
2pub struct Span {
3    pub start: usize,
4    pub end: usize,
5}
6
7impl Span {
8    pub fn new(start: usize, end: usize) -> Self {
9        Self { start, end }
10    }
11
12    /// Returns `true` if this [Span] overlaps with the other [Span].
13    ///
14    /// Will always return `false` when one of the spans is empty or invalid (`end < start`).
15    pub fn overlaps(&self, other: Span) -> bool {
16        self.start < other.end && other.start < self.end
17    }
18}
19
20#[cfg(test)]
21mod tests {
22    use super::*;
23
24    #[track_caller]
25    fn assert_overlap(a: Span, b: Span) {
26        let forward = a.overlaps(b);
27        let back = b.overlaps(a);
28        assert_eq!(forward, back);
29
30        assert!(
31            forward,
32            "Expected {a:?} and {b:?} to overlap but they don't."
33        );
34    }
35
36    #[track_caller]
37    fn assert_no_overlap(a: Span, b: Span) {
38        let forward = a.overlaps(b);
39        let back = b.overlaps(a);
40        assert_eq!(forward, back);
41
42        assert!(
43            !forward,
44            "Expected {a:?} and {b:?} not to overlap but they do."
45        );
46    }
47
48    #[test]
49    fn empty_spans_never_overlap() {
50        assert_no_overlap(Span { start: 0, end: 0 }, Span { start: 0, end: 0 });
51        assert_no_overlap(Span { start: 0, end: 0 }, Span { start: 10, end: 10 });
52        assert_no_overlap(Span { start: 100, end: 0 }, Span { start: 10, end: 10 });
53    }
54
55    #[test]
56    fn overlap_tests() {
57        assert_overlap(Span { start: 0, end: 10 }, Span { start: 5, end: 15 });
58        assert_overlap(Span { start: 5, end: 15 }, Span { start: 0, end: 10 });
59        assert_overlap(Span { start: 0, end: 10 }, Span { start: 0, end: 10 });
60        assert_overlap(Span { start: 0, end: 10 }, Span { start: 0, end: 5 });
61        assert_overlap(Span { start: 0, end: 10 }, Span { start: 5, end: 10 });
62
63        assert_no_overlap(Span { start: 10, end: 20 }, Span { start: 20, end: 30 });
64        assert_no_overlap(Span { start: 10, end: 20 }, Span { start: 30, end: 40 });
65    }
66}
cynic_parser/span.rs

cynic_parser/
span.rs
