TLDR: If you know enum_dispatch, this is very similar, except the macros work across crates, and there is some support for associated types.

Quick Walk-through

Add enum_delegate to each crate you plan to use it in:

enum_delegate = "0.1"

Annotate your trait with #[enum_delegate::register]:

#[enum_delegate::register]
trait SayHello {
    fn say_hello(&self, name: &str) -> String;
}

Create an enum with variants that all look like VariantName(VariantType). Each variant field must implement your trait. Now, annotate the enum with #[enum_delegate::implement(trait name)].

struct Arthur;
impl SayHello for Arthur {...}

struct Pablo;
impl SayHello for Pablo {...}

#[enum_delegate::implement(SayHello)]
enum People {
    Arthur(Arthur),
    Pablo(Pablo),
}

Your trait will be implemented for the enum, and conversions such as From<Arthur> and TryInto<Arthur> will also be generated. You can now use it similarly to a Box<dyn SayHello>, but it will be faster!

More Info

There is a more complete guide in the Readme. Also a few examples and tests in the repo.

Crates | Repository

For the macromancers among you, I also wrote an overview of what's going on behind the scenes: How does it work?