some-error 0.5.0

A library for allowing Anonymous Sum Types in the error of the returned result. The function this is attached to must return a type in the form of Result<T, E1 + E2 + ...>.

Example:

use std::io;
use some_error::*;

#[derive(Debug, Clone, Copy)]
struct NotZeroError(u32);

#[some_error]
fn my_func() -> Result<(), io::Error + NotZeroError>{
let x = 3;
if x != 0 {
Err(NotZeroError(x))?;
}

Ok(())
}

fn main() {
match my_func() {
Ok(_) => {
println!("Worked ok!");
}
Err(my_func::NotZeroError(NotZeroError(x))) => {
println!("{} is not zero!!", x);
}
Err(my_func::io::Error(io_err)) => {
println!("io error: {:?}", io_err);
}
}
}