gistfile1.txt

enum OrderEvent {
    OrderPlaced(OrderPlacedPayload)
}

struct OrderPlacedPayload {
    name: String,
    whatever: String
}

mod event_formats {
    struct OrderPlacedPayloadV1 {
        name: String
    }
    
    impl Into<OrderPlacedPayloadV2> for OrderPlacedPayloadV1 {
        // Convert v1 into v2
    }
    
    struct OrderPlacedPayloadV2 {
        name: String,
        whatever: String
    }
    
    impl Into<OrderPlacedPayload> for OrderPlacedPayloadV2 {
        // Convert v2 into main payload
    }
}

fn load_order(event_name: String, event_version: String, payload: json::Value) -> OrderPlacedPayload {
    match (event_name, event_version) {
        ("OrderPlaced", "v1") => serde_json::from_value::<OrderPlacedPayloadV1>(payload)
            .into::<OrderPlacedPayloadV2>()
            .into::<OrderPlacedPayload>();
        ("OrderPlaced", "v2") => serde_json::from_value::<OrderPlacedPayloadV2>(payload)
            .into::<OrderPlacedPayload>();
    }
}