Dunai is a DSL for strongly-typed CPS-based composable transformations.
Dunai is based on a concept of Monadic Stream Functions (MSFs). MSFs are
transformations defined by a function
unMSF :: MSF m a b -> a -> m (b, MSF m a b)
that executes one step of a simulation, and produces an output in a monadic
context, and a continuation to be used for future steps.
MSFs are a generalisation of the implementation mechanism used by Yampa, Wormholes and other FRP and reactive implementations.
When combined with different monads, they produce interesting effects. For
example, when combined with the
Maybe monad, they become transformations
that may stop producing outputs (and continuations). The
Either monad gives
rise to MSFs that end with a result (akin to Tasks in Yampa, and Monadic
Flattening, that is, going from some structure
MSF (t m) a b to
MSF m a b
for a specific transformer
t often gives rise to known FRP constructs. For
instance, flattening with
EitherT gives rise to switching, and flattening
ListT gives rise to parallelism with broadcasting.
MSFs can be used to implement many FRP variants, including Arrowized FRP, Classic FRP, and plain reactive programming. Arrowized and applicative syntax are both supported.