Function constmuck::wrapper::wrap

pub const fn wrap<Outer, Inner>(
    val: Inner, 
    _bound: IsTransparentWrapper<Outer, Inner>
) -> Outer

Casts Inner to Outer

Requires that Outer implements TransparentWrapper<Inner>

Example

use constmuck::{IsTW, wrapper};

#[derive(Debug, PartialEq)]
#[repr(transparent)]
pub struct Qux<T>(pub T);

unsafe impl<T> constmuck::TransparentWrapper<T> for Qux<T> {}


// Casting `&u32` to `Qux<u32>`
//
// `IsTW!()` is a more concise way to write `IsTransparentWrapper::NEW`
const VALUE: Qux<u32> = wrapper::wrap(3, IsTW!());

assert_eq!(VALUE, Qux(3));

// `IsTW!(Qux<_>)` is required because any type can implement comparison with `Qux`.
assert_eq!(wrapper::wrap(3, IsTW!(Qux<_>)), Qux(3));


// Casting `[u32; 3]` to `[Qux<u32>; 3]`
//
// The `.array()` is currently required to cast arrays of values into arrays of
// wrappers around those values.
const ARR: [Qux<u32>; 3] = wrapper::wrap([5, 8, 13], IsTW!(Qux<u32>, u32).array());

assert_eq!(ARR, [Qux(5), Qux(8), Qux(13)]);

assert_eq!(
    wrapper::wrap([5, 8, 13], IsTW!(Qux<_>).array()),
    [Qux(5), Qux(8), Qux(13)],
);