Event.hs

-- | Event type class. All events that can be applied to aggregate roots
-- are required have an instance for this class.
module Data.CQRS.Event
       ( Event(..)
       ) where

-- | Event class for applying events to aggregates.
class Event e a | e -> a where
  -- | Apply an event to the aggregate and return the updated aggregate.
  applyEvent :: e -> a -> a