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Abstract: “Functional reactive programming, or FRP, is a paradigm for programming hybrid systems – i.e., systems containing a combination of both continuous and discrete components – in a high-level, declarative way. The key ideas in FRP are its notions of continuous, time-varying values, and time-ordered sequences of discrete events.

Yampa is an instantiation of FRP as a domain-specific language embedded in Haskell. This paper describes Yampa in detail, and shows how it can be used to program a particular kind of hybrid system: a mobile robot. Because performance is critical in robotic programming, Yampa uses arrows (a generalization of monads) to create a disciplined style of programming with time-varying values that helps ensure that common kinds of time- and space-leaks do not occur.

No previous experience with robots is expected of the reader, although a basic understanding of physics and calculus is assumed. No knowledge of arrows is required either, although we assume a good working knowledge of Haskell.”