#enums #enum-variant #building #macro #animal #dog #fish #enum-dispatch

macro enum_builder

Simple macros that allow building enum types from variants that can be defined in multiple dispersed files in the crate

7 releases

Uses new Rust 2024

0.1.6 Jul 5, 2025
0.1.5 Jul 5, 2025

#548 in Procedural macros

MIT license

10KB
181 lines

enum_builder

Simple macros that allow building enum types from variants that can be defined in multiple dispersed files in the crate.

Crates.io Documentation License GitHub

Example

main.rs

mod animals;

use animals::*;

#[enum_builder]
enum Animal {}

// expanded result
// enum Animal {
//     Dog(Dog),
//     Cow(Cow),
//     Fish(Fish),
// }

animals.rs

#[enum_builder_variant(Animal)]
struct Dog {}

#[enum_builder_variant(Animal)]
struct Cow {}

#[enum_builder_variant(Animal)]
struct Fish {}

Tips

It can be very useful to combine this crate with the enum_dispatch crate, to allow for a simple "plugin" architecture without the overhead of dynamic dispatch. When doing this, take care to note that the order of macros is important, as enum_builder must be used before enum_dispatch.

Example

#[enum_builder]
#[enum_dispatch]
enum Animal {}

Dependencies

~0.3–2.4MB
~46K SLoC