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
76
77
78
79
80
81
|
#![deny(clippy::pedantic)]
#![deny(clippy::all)]
//! Tests if multiple generic parameters work, for the case that lifetimes are independent of mapping functions.
//! For simplicity, it just creates a `FreeResult` based on `Result`.
use higher_free_macro::free;
use higher::{Functor, Bind, Apply};
free!(FreeResult<O,E>, Result<FreeResult<O,E>,E>);
//just to appease clippy without disabling the lint....
macro_rules! assert_nearly_equal {
($a:expr, $b:expr, $c:expr) => {
assert!((($a)-($b)).abs() < $c)
};
}
#[test]
fn test_multiple_generics(){
let m : FreeResult<_, String> = FreeResult::lift_f(Ok(37u32));
let m = m.fmap(|x| x*2);
let m = m.bind(|x| FreeResult::Free(Box::new(Ok(FreeResult::Pure(x)))));
let f = FreeResult::Pure((|x| x*3).into());
let m = m.apply(f);
match m {
FreeResult::Free(b) => {
match *b {
Ok(FreeResult::Free(b)) => {
match *b {
Ok(FreeResult::Pure(x)) => assert_eq!(x, 37*6),
_ => unreachable!()
}
}
_ => unreachable!()
}
}
FreeResult::Pure(_) => unreachable!()
}
}
#[test]
fn test_multiple_generics2(){
let m : FreeResult<_, String> = FreeResult::lift_f(Ok(37u32));
let m = m.bind(|_| FreeResult::<u32, _>::lift_f(Err("An early out.".to_owned())));
match m{
FreeResult::Free(m) => {
match &*m {
Ok(FreeResult::Free(m)) => {
match &**m {
Err(e) => assert_eq!(e, "An early out."),
_ => unreachable!()
}
},
_ => unreachable!()
}
},
FreeResult::Pure(_) => unreachable!()
}
}
#[test]
fn test_multiple_generics3(){
let m : FreeResult<_, String> = FreeResult::lift_f(Ok(37u32));
let f : FreeResult<_, String> = FreeResult::Pure(|x : u32| -> f64 {f64::from(x)*0.5f64}).fmap(Into::into);
let m = m.apply(f);
match m{
FreeResult::Free(m) => {
match &*m{
Ok(k) => {
match k {
FreeResult::Pure(k) => assert_nearly_equal!(18.5f64, *k, f64::EPSILON),
FreeResult::Free(_) => unreachable!(),
}
}
Err(_) => unreachable!(),
}
},
FreeResult::Pure(_) => unreachable!()
}
}
|
