Hi Corentin,
I have a DSL like this: data Exp where OnEvent :: EventName -> (Int -> Exp) -> Exp (...)
The "OnEvent" element carries a function (the handler to be called when the event happens), and that makes my DSL non showable/serializable. How could I fix that? This is a real handicap not to be able to serialize the state of my whole application because of that :)
You could have a unique id for your handlers, which might be an Int or a String and have some kind of registration for the handlers. data Exp where OnEvent :: EventName -> HandlerId -> Exp type HandlerId = String type Handler = (Int -> Exp) type Handlers = HashMap HandlerId Handler registerHandler :: Handlers -> (HandlerId, Handler) -> Handlers getHandler :: Handlers -> HandlerId -> Maybe Handler But you have to ensure, that for each application run the same HandlerId also gets the same Handler. Less flexible but more secure is an ADT for you Handler. data Handler = DoThat | DoSometingElse You can than just pattern match on your handler and don't need any kind of registration. But you can go further and define your own little Handler DSL. Greetings, Daniel