How to declare typed bitflags in Rust?

Question

It\'s possible to declare flags in Rust - similar to how it would be done in C.

pub const FOO: u32 = (1 << 0);
pub const BAR: u32 = (1 << 1);

let fl         


        

Answer 1

You could (I don't know if it is in any way idiomatic) just use Rust's enums :

pub enum MyFlags {
    Meaning1,
    Meaning2,
    Meaning3,
    ...,
    MeaningX
}

This way you have a clear meaning for your flags. Once done, you can write some helper functions around this enum for Rust-to-C conversion.

fn to_u32(flag: &MyFlags) -> u32 {
    match flag {
        &MyFlags::Meaning1 => return (1 << 0),
        &MyFlags::Meaning2 => return (1 << 1),
        &MyFlags::Meaning3 => return (1 << 2),
        &MyFlags::MeaningX => return (1 << 3),
    }
}

fn to_bitflags_flags(flags: &Vec) -> u32 {
    let mut bitflags = 0u32;

    for flag in flags {
        bitflags |= to_u32(flag);
    }
    return bitflags;
}