dcbor_pattern/pattern/value/
null_pattern.rs

1use dcbor::prelude::*;
2
3use crate::pattern::{Matcher, Path, Pattern, vm::Instr};
4
5/// Pattern for matching null values in dCBOR.
6#[derive(Debug, Clone, Hash, Eq, PartialEq, Default)]
7pub struct NullPattern;
8
9impl Matcher for NullPattern {
10    fn paths(&self, haystack: &CBOR) -> Vec<Path> {
11        if haystack.is_null() {
12            vec![vec![haystack.clone()]]
13        } else {
14            vec![]
15        }
16    }
17
18    fn compile(
19        &self,
20        code: &mut Vec<Instr>,
21        literals: &mut Vec<Pattern>,
22        _captures: &mut Vec<String>,
23    ) {
24        let idx = literals.len();
25        literals.push(Pattern::Value(crate::pattern::ValuePattern::Null(
26            self.clone(),
27        )));
28        code.push(Instr::MatchPredicate(idx));
29    }
30}
31
32impl std::fmt::Display for NullPattern {
33    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
34        write!(f, "null")
35    }
36}
37
38#[cfg(test)]
39mod tests {
40    use super::*;
41
42    #[test]
43    fn test_null_pattern_matching() {
44        let null_cbor = CBOR::null();
45        let pattern = NullPattern;
46        let paths = pattern.paths(&null_cbor);
47        assert_eq!(paths.len(), 1);
48        assert_eq!(paths[0], vec![null_cbor.clone()]);
49
50        // Test with non-null CBOR
51        let text_cbor = "test".to_cbor();
52        let paths = pattern.paths(&text_cbor);
53        assert!(paths.is_empty());
54
55        let number_cbor = 42.to_cbor();
56        let paths = pattern.paths(&number_cbor);
57        assert!(paths.is_empty());
58    }
59
60    #[test]
61    fn test_null_pattern_display() {
62        assert_eq!(NullPattern.to_string(), "null");
63    }
64
65    #[test]
66    fn test_null_pattern_matches() {
67        let pattern = NullPattern;
68        let null_cbor = CBOR::null();
69        assert!(pattern.matches(&null_cbor));
70
71        let text_cbor = "test".to_cbor();
72        assert!(!pattern.matches(&text_cbor));
73
74        let bool_cbor = true.to_cbor();
75        assert!(!pattern.matches(&bool_cbor));
76    }
77}
dcbor_pattern/pattern/value/null_pattern.rs

dcbor_pattern/pattern/value/
null_pattern.rs
