Derive Macro Aggregate 

#[derive(Aggregate)]
{
    // Attributes available to this derive:
    #[aggregate]
}

Derives the Aggregate trait for a struct.

This macro generates:

• An event enum containing all aggregate event types
• EventKind trait implementation for runtime kind dispatch
• ProjectionEvent trait implementation for event deserialisation
• From<E> implementations for each event type
• Aggregate trait implementation that dispatches to Apply<E> for events

Note: Commands are handled via individual Handle<C> trait implementations. No command enum is generated - use execute_command::<Aggregate, Command>() directly.

Attributes

Required

• id = Type - Aggregate ID type
• error = Type - Error type for command handling
• events(Type1, Type2, ...) - Event types

Optional

• kind = "name" - Aggregate type identifier (default: lowercase struct name)
• event_enum = "Name" - Override generated event enum name (default: {Struct}Event)
• derives(Trait1, Trait2, ...) - Additional derives for the generated event enum. Always includes Clone and serde::Serialize. Common additions: Debug, PartialEq, Eq

Example

#[derive(Aggregate)]
#[aggregate(
    id = String,
    error = String,
    events(FundsDeposited, FundsWithdrawn),
    derives(Debug, PartialEq, Eq)
)]
pub struct Account {
    balance: i64,
}