Miguel Negrao wrote:
Hi list,
I would like to implement a certain type of throttling of events in reactive-banana. It should work such that an event is not let through if arrives at less then delta seconds from the last event that passed through. If it is not let through then it is stored and is fired after delta seconds from the last fired event.
Below is a program that implements this for lists of time stamped numbers. Would it be possible to translate this to reactive-banana ?
Also, in reactive-banana how do I fire an event x seconds after some other event comes in. The way I would do it in scala’s reactive-web is to start a timer that fires x seconds after it is started when an event comes in using dynamic event switching . It seems to me this would not be possible in reactive-banana because starting a timer is an IO operation, so I assume it can’t be done inside the event/behavior logic, right ?
Miguel, could you repost this question on Stackoverflow, so I can answer it there? This way, questions about reactive-banana are easier to find later on. http://stackoverflow.com/questions/ask?tags=reactive-programming+haskell+frp As for the answer, it is possible to implement the functionality you desire in reactive-banana, though it is a little involved. Basically, you have use an external framework like wxHaskell to create a timer, which you can then use to schedule events. The Wave.hs example from the examples pages demonstrates how to do that. Put differently, I have opted to not include time in the reactive-banana library itself. The reason is simply that different external framework have timers of different resolution or quality, there is no one-size that fits it all. I do intend to add common helper functions that deal with time and timers to the library itself, but I still need to find a good way to make it generic over different timers and figure out which guarantees I can provide. Best regards, Heinrich Apfelmus -- http://apfelmus.nfshost.com