Hi everyone,
I am experimenting with various implementation styles for classical FRP. My
current thoughts are on a continuation-style push implementation, which can be
summarized as follows.
> newtype EventT m r a = E { runE :: (a -> m r) -> m r -> m r }
> newtype ReactiveT m r a = R { runR :: (m a -> m r) -> m r }
> type Event = EventT IO ()
> type Reactive = ReactiveT IO ()
The idea is that events allow subscription of handlers, which are automatically
unsubscribed after the continuation has finished, while reactives allow
observation of a shared state until the continuation has finished.
I managed to write the following Applicative instance
> instance Applicative (ReactiveT m r) where
> pure a = R $ \k -> k (pure a)
> R f <*> R a = R $ \k -> f (\f' -> a (\a' -> k $ f' <*> a'))
But I am stuck on finding a suitable Monad instance. I notice the similarity
between my types and the ContT monad and have a feeling this similarity could
be used to clean up my instance code, but am not sure how to proceed. Does
anyone have an idea, or a pointer to suitable literature.
Best regards,
Hans_______________________________________________
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