Support for deriving traits found in uncon.

Usage

This crate is available on crates.io and can be used by adding the following to your project's Cargo.toml:

[dependencies]
uncon_derive = "1.0.4"
uncon = "1.1.0"

and this to your crate root:

#[macro_use]
extern crate uncon_derive;
extern crate uncon;
# fn main() {}

Examples

The FromUnchecked trait can be derived for:

• Structs with a single field
• C-like enums with #[repr] attribute

# extern crate core;
# #[macro_use] extern crate static_assertions;
# #[macro_use] extern crate uncon_derive;
# extern crate uncon;
# use uncon::*;
# macro_rules! assert_impl_from {
#     ($t:ty, $($u:ty),+) => { assert_impl!($t, $(FromUnchecked<$u>),+) }
# }
#[derive(FromUnchecked)]
struct U4 {
    bits: u8
}

#[derive(FromUnchecked, PartialEq, Debug)]
#[uncon(other(u16, u32, u64, usize))]
# #[uncon(other(i8, i16, i32, i64, isize))]
#[repr(u8)]
enum Flag {
    A, B, C, D
}

// `usize` and `isize` also supported:
#[derive(FromUnchecked)]
#[repr(usize)]
enum Value {
    X, Y, Z
}

# fn main() {
# assert_impl_from!(Flag, u8, u16, u32, u64, usize);
# assert_impl_from!(Flag, i8, i16, i32, i64, isize);
unsafe {
    let b = 0b1010;
    let x = U4::from_unchecked(b);
    assert_eq!(x.bits, b);

    let n = 2u8;
    let f = Flag::from_unchecked(n);
    assert_eq!(f, Flag::C);

    // Done via `#[uncon(other(u32, ...))]`
    let f = Flag::from_unchecked(n as u32);
}
# }