const_str/__ctfe/
unwrap.rs

1pub struct Unwrap<T>(pub T);
2
3impl<T: Copy> Unwrap<Option<T>> {
4    pub const fn const_eval(self) -> T {
5        match self.0 {
6            Some(x) => x,
7            None => panic!("called `Option::unwrap()` on a `None` value"),
8        }
9    }
10}
11
12/// Unwraps a container, returns the content.
13///
14/// The input type must be one of
15/// + [`Option<T>`], where `T: Copy`.
16///
17/// The [`Copy`] bound may be relaxed in the future.
18///
19/// This macro is [const-fn compatible](./index.html#const-fn-compatible).
20#[macro_export]
21macro_rules! unwrap {
22    ($expr: expr) => {{
23        $crate::__ctfe::Unwrap($expr).const_eval()
24    }};
25}
26
27#[cfg(test)]
28mod tests {
29    use super::*;
30
31    #[test]
32    fn test_unwrap_some() {
33        const X: Option<i32> = Some(42);
34        const Y: i32 = unwrap!(X);
35        assert_eq!(Y, 42);
36
37        const S: Option<&str> = Some("hello");
38        const T: &str = unwrap!(S);
39        assert_eq!(T, "hello");
40
41        let b: Option<bool> = Some(true);
42        let c: bool = unwrap!(b);
43        assert!(c);
44    }
45
46    #[test]
47    fn test_unwrap_runtime() {
48        // Runtime tests for Unwrap
49        let unwrap_some = Unwrap(Some(42));
50        assert_eq!(unwrap_some.const_eval(), 42);
51
52        let unwrap_str = Unwrap(Some("test"));
53        assert_eq!(unwrap_str.const_eval(), "test");
54
55        let unwrap_bool = Unwrap(Some(false));
56        assert!(!unwrap_bool.const_eval());
57    }
58}
const_str/__ctfe/unwrap.rs

const_str/__ctfe/
unwrap.rs
