View adapters

[NickSeagull]

At the time of writing this issue, the view function from the user has the signature:

view :: Model -> Text

Platform is executing it as-is, and rendering it. The next step would be to use some other type like Html to allow structured rendering, but views could be used also for GET endpoints for backends:

Essentially, a view is a way of seeing the state of the application in a specific way.

Given that in NeoHaskell the state is (conceptually) a single record, it makes sense to allow defining views that are executed on demand.

Right now the demand is handled by the platform automatically (when a new frame has to be rendered, it executes the function and renders it using a render :: Text -> IO () function).

This means that we have two functions that work together for the sake of the proper "viewing" of the model:

view :: Model -> Text

render :: Text -> IO ()

We should allow to provide, for example, an HTTP server view adapter, so the user can write a view function that outputs JSON, and the HTTP server returns it back.

This should be extendable to anything that can query data: GRPC, IPC, sockets, whatever