Introduction

Moxy is a Rust derive macro crate that eliminates boilerplate. Get Display, Deref, Default, Build, Get, Set, Union, and Forward implementations with a single attribute — no hand-written impl blocks needed.

What You Get

• Display — Flexible std::fmt::Display with multiple output formats, JSON serialization, and colored terminal output.
• Deref — Automatic std::ops::Deref delegation to inner fields.
• Build — Type-safe fluent builder with compile-time field tracking, V: Into<T> setters, and inline defaults.
• Default — std::default::Default with per-field custom expressions via #[moxy(default = expr)].
• Get — Field getters returning Deref::Target (e.g. String → &str), with copy/clone/mutable modifiers and callbacks.
• Set — Field setters with Into<T> coercion, Option<T> auto-wrapping, transform callbacks, and chaining.
• Union — Enum variant accessors (is_*, as_*, to_*), common field detection, and the unionize! shorthand macro.
• Forward — Forward method calls to inner fields (structs) or variant payloads (enums) by declaring method signatures.

Quick Example

use moxy::{Deref, Display};

#[derive(Deref, Display)]
#[moxy(display(debug, pretty))]
struct User {
    #[moxy(deref)]
    name: String,
    email: String,
}

let user = User {
    name: "John".into(),
    email: "john@example.com".into(),
};

// Display output:
// User {
//     name: "John",
//     email: "john@example.com",
// }

// Deref delegates to name:
assert_eq!(user.len(), 4);

Inspiration

Moxy draws ideas from these excellent crates:

• ambassador
• getset
• bon
• thiserror
• derive_more
• strum

License

MIT