Observer patern using the standard FRP conventions? Are these situations inside the aims of FRP? There are several flavours of FRP that approach reactivity from different angles. I'd say Grapefruit is the one most relevant to the Observer pattern, since it models complex systems as a network of interconnected circuits, where circuits are effectful entities, and they can communicate through both discrete and continuous signals. The other system that might be relevant is Yampa, since you model entities as stateful signal functions (but unlike in Grapefruit they cannot perform side effects), and connect them however you want. Incidentally, both of
Hi Alvaro, these approaches are arrow based. In contrast, Reactive aims to describe the (output over the) whole lifetime of an entity as a pure value. Dependencies between entities are established simply by defining one as a function of the other, and mutual dependencies are naturally allowed. I don't think there's any meaningful way to connect the Observer pattern to that. In fact, the basic OO design patterns are often meaningless in functional programming, because it's a completely different world. Gergely -- http://www.fastmail.fm - Or how I learned to stop worrying and love email again