Elerea (Eventless reactivity) is a tiny discrete time FRP implementation
without the notion of event-based switching and sampling, with first-class
signals (time-varying values). Reactivity is provided through various
higher-order constructs that also allow the user to work with arbitrary
time-varying structures containing live signals. Signals have precise and
simple denotational semantics.
Stateful signals can be safely generated at any time through a monadic
interface, while stateless combinators can be used in a purely applicative
style. Elerea signals can be defined recursively, and external input is trivial
to attach. The library comes in two major variants:
This is a minimal library that defines only some basic primitives, and you are
advised to install 'elerea-examples' as well to get an idea how to build
non-trivial systems with it. The examples are separated in order to minimise
the dependencies of the core library. The 'dow' package contains a full game
built on top of the simple variant.
The basic idea of the implementation is described in the WFLP 2010 paper
/Efficient and Compositional Higher-Order Streams/
Additional contributions: Takano Akio, Mitsutoshi Aoe.