enum2contract

enum2contract is a no_std compatible rust derive macro that lets users specify contracts for pub/sub style messaging using strongly typed rust enums.

Each generated payload derives Default, Debug, Clone, and PartialEq, and gets JSON (to_json/from_json) and binary (to_bytes/from_bytes) conversion methods.

Usage

Add this to your Cargo.toml:

enum2contract = "0.3"

No other dependencies are required; the crate re-exports serde, serde_json, and postcard for the generated code.

Example:

use enum2contract::EnumContract;

#[derive(EnumContract)]
pub enum Message {
    #[topic("notify/{group}")]
    Notify,

    #[topic("notify_all")]
    NotifyAll,

    #[topic("system/{id}/start/{mode}")]
    Start { immediate: bool, timeout: u64 },
}

#[test]
fn topic() {
    assert_eq!(Message::notify_topic("subset"), "notify/subset");

    assert_eq!(Message::notify_all_topic(), "notify_all");

    assert_eq!(
        Message::start_topic(&3.to_string(), "idle"),
        "system/3/start/idle"
    );
}

#[test]
fn message() {
    assert_eq!(
        Message::notify("subgroup"),
        ("notify/subgroup".to_string(), NotifyPayload::default())
    );

    assert_eq!(
        Message::notify_all(),
        ("notify_all".to_string(), NotifyAllPayload::default())
    );

    assert_eq!(
        Message::start(&3.to_string(), "idle"),
        ("system/3/start/idle".to_string(), StartPayload::default())
    );
}

#[test]
fn notify_payload_from_json_with_data() {
    let json = r#"{"immediate":true,"timeout":40}"#;
    let payload = StartPayload::from_json(json).unwrap();
    assert_eq!(
        payload,
        StartPayload {
            immediate: true,
            timeout: 40,
        }
    );
}

#[test]
fn start_payload_binary_round_trip() {
    let payload = StartPayload {
        immediate: true,
        timeout: 40,
    };
    let bytes = payload.to_bytes().unwrap();
    assert_eq!(StartPayload::from_bytes(&bytes).unwrap(), payload);
}

This crate is #![no_std] compatible but requires alloc.

enum2contract 0.3.0

enum2contract

Usage