crepe 0.2.0

Datalog in Rust as a procedural macro
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32

// This test checks the functionality of disaggregates, or the `for` keyword.

use crepe::crepe;

crepe! {
    @input
    struct Name<'a>(&'a str);

    @output
    #[derive(Debug, PartialOrd, Ord)]
    struct NameContainsLetter<'a>(&'a str, char);

    NameContainsLetter(name, letter) <- Name(name), for letter in name.chars();
}

#[test]
fn test_disaggregate() {
    let mut rt = Crepe::new();
    rt.extend([Name("al"), Name("bob")]);
    let (res,) = rt.run();
    let mut res: Vec<_> = res.into_iter().collect();
    res.sort();
    assert_eq!(
        res,
        vec![
            NameContainsLetter("al", 'a'),
            NameContainsLetter("al", 'l'),
            NameContainsLetter("bob", 'b'),
            NameContainsLetter("bob", 'o'),
        ],
    );
}