exhaust is a small trait-and-derive-macro library providing the Exhaust trait, which allow iterating over all values of a given type (both std types and your own structs and enums via #[derive(Exhaust)]).

use exhaust::Exhaust;

#[derive(PartialEq, Debug, Exhaust)]
struct Foo {
    a: bool,
    b: Bar,
}

#[derive(PartialEq, Debug, Exhaust)]
enum Bar {
    One,
    Two(bool),
}

assert_eq!(
    Foo::exhaust().collect::<Vec<Foo>>(),
    vec![
        Foo { a: false, b: Bar::One },
        Foo { a: false, b: Bar::Two(false) },
        Foo { a: false, b: Bar::Two(true) },
        Foo { a: true, b: Bar::One },
        Foo { a: true, b: Bar::Two(false) },
        Foo { a: true, b: Bar::Two(true) },
    ],
);

exhaust is useful for:

• testing functions of enums and small structs with 100% coverage,
• building lookup tables,
• brute force searches,
• and anything else where you want to compute or initialize something for every possible case specified by a type.

Today I released v0.2.5, which reduces code size and memory usage, and offers the factory_is_self option for deriving less code when possible. It’s not a flashy release with powerful new features, but I think that reflects that exhaust is a reliable library for its one purpose, so I thought it would be a good time to tell you about it for the first time. (Why not 1.0 yet?)

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