lib-tan-core 0.16.0

The core library
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
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56

use std::cmp::Ordering;

use tan::{
    context::Context,
    expr::{annotate_type, Expr},
    util::module_util::require_module,
};

use super::{arithmetic, string::string_compare};

pub fn rust_ordering_from_tan_ordering(tan_ordering: &Expr) -> Option<Ordering> {
    let ordering = tan_ordering.as_int()?;
    Some(ordering.cmp(&0))
}

pub fn setup_lib_cmp(context: &mut Context) {
    let module = require_module("prelude", context);

    // cmp

    // #todo `eq` and `Comparable` are related.
    // #todo consider to make sorter: `cmp`.

    module.insert_invocable("compare", Expr::foreign_func(&arithmetic::int_compare));
    module.insert_invocable(
        "compare$$Int$$Int",
        annotate_type(Expr::foreign_func(&arithmetic::int_compare), "Int"),
    );
    module.insert_invocable(
        "compare$$String$$String",
        annotate_type(Expr::foreign_func(&string_compare), "String"),
    );
}

#[cfg(test)]
mod tests {
    use std::cmp::Ordering;

    use assert_matches::assert_matches;

    use tan::expr::Expr;

    use crate::cmp::rust_ordering_from_tan_ordering;

    #[test]
    fn rust_ordering_from_tan_ordering_usage() {
        assert_matches!(
            rust_ordering_from_tan_ordering(&Expr::Int(20)),
            Some(Ordering::Greater)
        );
        assert_matches!(
            rust_ordering_from_tan_ordering(&Expr::Int(0)),
            Some(Ordering::Equal)
        );
    }
}