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//! Various macro for IC canisters to enable event-based pub/sub
//!
//! Usage:
//! ```
//! // somewhere in your canister
//! implement_event_emitter!();
//! implement_subscribe!();
//! implement_unsubscribe!();
//!
//! ...
//!
//! #[derive(Event)]
//! struct Event {
//! #[topic]
//! pub a: u64,
//! pub b: String,
//! }
//!
//! emit(Event {
//! a: 10,
//! b: String::from("test")
//! });
//! ```
//!
//! Check the [companion crate](https://crates.io/crates/ic-event-hub) to see how a listener could
//! start receiving events
#![warn(missing_docs)]
use crate::derive::event_macro_impl;
use proc_macro::TokenStream;
mod derive;
/// Generates an implementation of `ic_event_hub::types::IEvent` trait for a given struct. Also generates a `*Filter`
/// struct and an implementation of `ic_event_hub::types::IEventFilter` trait for that struct which can be used to filter
/// topics while listening to the given event.
///
/// Fields of the event struct have to implement `candid::CandidType` and `candid::Deserialize`
///
/// Usage:
/// ```
/// #[derive(Event)]
/// struct MyEvent {
/// ...
/// }
/// ```
#[proc_macro_derive(Event, attributes(topic))]
pub fn event_macro_derive(input: TokenStream) -> TokenStream {
event_macro_impl(input)
}