functor_derive 0.4.3

A derive macro to derive a functor for a type.
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
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75

use crate::funcmap::{T1, T2};
use functor_derive::Functor;

#[test]
fn field_of_generic_param_type_is_mapped() {
    #[derive(Functor, Debug, PartialEq)]
    struct Test<T>(T);

    let src = Test(T1);
    let dst = src.fmap(|_| T2);

    assert_eq!(dst, Test(T2));
}

#[test]
fn field_of_generic_type_is_mapped() {
    #[derive(Functor, Debug, PartialEq)]
    struct Inner<T>(T);

    #[derive(Functor, Debug, PartialEq)]
    struct Test<T>(Inner<T>);

    let src = Test(Inner(T1));
    let dst = src.fmap(|_| T2);

    assert_eq!(dst, Test(Inner(T2)));
}

#[test]
fn field_of_nested_generic_type_is_mapped() {
    #[derive(Functor, Debug, PartialEq)]
    struct Inner<T>(T);

    #[derive(Functor, Debug, PartialEq)]
    struct Test<T>(Inner<Inner<T>>);

    let src = Test(Inner(Inner(T1)));
    let dst = src.fmap(|_| T2);

    assert_eq!(dst, Test(Inner(Inner(T2))));
}

#[test]
fn field_of_non_generic_type_is_not_mapped() {
    #[derive(Functor, Debug, PartialEq)]
    struct Test<T>(T, i32);

    let src = Test(T1, 42);
    let dst = src.fmap(|_| T2);

    assert_eq!(dst, Test(T2, 42));
}

#[test]
fn parenthesized_generic_param_is_mapped() {
    #[allow(unused_parens)]
    #[derive(Functor, Debug, PartialEq)]
    struct Test<T>((T));

    let src = Test(T1);
    let dst = src.fmap(|_| T2);

    assert_eq!(dst, Test(T2));
}

#[test]
fn tuple_entry_of_generic_param_type_is_mapped() {
    #[derive(Functor, Debug, PartialEq)]
    struct Test<T>((T, i32, T));

    let src = Test((T1, 42, T1));
    let dst = src.fmap(|_| T2);

    assert_eq!(dst, Test((T2, 42, T2)));
}