Re: [Haskell-beginners] FRP

A 20/09/2012, às 03:56, Ertugrul Söylemez escreveu:

Miguel Negrao wrote:

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Netwire follows a more algebraic path and drops the classic notion. The line between signals and events is blurred. It's a bit more difficult to understand, but is more expressive and concise. Also it's pretty much time-leak-free. The library is designed to be very elegant while preserving non-FRP performance to a high degree.

(To be fair, I'm the author of Netwire.) =)

Having recently looked a bit on Yampa, what are the main differences between Yampa and Netwire ?

The way events are handled. Yampa uses the classic automaton category with an additional time delta argument for its signal function [...]

Thanks for the explanation. I was wondering, how would one translate this Yampa code into reactive-banana: fallingBall :: Pos -> Vel -> SF () (Pos, Vel) fallingBall y0 v0 = proc () -> do v <- (v0 +) ˆ<< integral -< -9.81 y <- (y0 +) ˆ<< integral -< v returnA -< (y, v) fallingBall’ :: Pos -> Vel -> SF () ((Pos,Vel), Event (Pos,Vel)) fallingBall’ y0 v0 = proc () -> do yv@(y, _) <- fallingBall y0 v0 -< () hit <- edge -< y <= 0 returnA -< (yv, hit ‘tag‘ yv) bouncingBall :: Pos -> SF () (Pos, Vel) bouncingBall y0 = bbAux y0 0.0 where bbAux y0 v0 = switch (fallingBall’ y0 v0) $ \(y,v) -> bbAux y (-v) Would it be possible to do this without dynamic event switching ? What about with the new event switching in v0.7 ? Also, is it possible (and is it easy ?) to do looping such as it is done in Yampa using the the loop arrow in reactive-banana/classic FRP ? best, Miguel Negrão