Hello, I'm trying to implement something like the Observer pattern in a functional setting. Some people told me that maybe I will find what I want in FRP. The Observer pattern enforces the propagation of changes in the subject to the observers, but in a way where concurrency is not considered, through the notify-update mechanism. Time is not considered because the updating methods are invoked in a synchronous way. Other way to say it is that time is a discrete value which is incremented by one with any subject change and the observers use a pooling strategy in every instance of time. The subject and the observers operate in the same thread. As far as I've seen (but I'm not sure if I'm right) FRP models behaviours and time as continuous entities (although practical implementations use discrete time and discrete sampling in event detection). You must represent the time explicitly and concurrency is used to model behaviors and events. Is there any interpretation of FRP without using concurrency? Can the time be modeled in a discrete fashion (as described for the Observer pattern)? I didn't find any example of that. Is it possible to model something like the Observer patern using the standard FRP conventions? Are these situations inside the aims of FRP? I think the Observer pattern and FRP are related somehow, but I cannot figure out how is this. Alvaro.