I know that this is an advanced group but I am hoping someone can give us a little help .. [Boring History Begins] I and one of my students have been excitedly experimenting with Reactive. We're not Haskell pros but have written lots of Haskell code, including an HopenGL Logo, a computer architecture simulator, and an HopenGL conventional robot wall follower simulator. (screenshot and code are available here, http://www.softcomp.com/haskell/wallfollow/wf02.png http://www.softcomp.com/haskell/wallfollow/wf01.tar.gz ) Our goal is to rewrite the conventional wall follower robot simulation in Reactive. We're happy to publish it once it's working. Several months ago Jules Bean posted 'stars' (to the group) a demo of a reactive framework similar to, but not identical to Colin's. Inside 'stars' was a file containing several very simple reactive examples (very useful to us newbies). http://www.softcomp.com/haskell/wallfollow/JulesReactiveDemo.hs Source .. including support libraries (Deus subdirectory) is here, http://www.softcomp.com/haskell/wallfollow/JulesReactiveDemo.tar.gz After experimenting with these we wrote a reactive robot controller which is supposed to wall follow. This controller code produces a file (this way we didn't have to rewrite to GUI portion too) to be input later to a visual 'player'. Unfortunately it just hangs and produces no output. [Boring History Ends] Undaunted we stepped back and wrote an extremely simple thermostat / furnace controller. This exhibits the same untoward hanging behavior on a blocking read inside 'runReactor'. The code for the main program is given far below. Full code (including the Deus directory, where all of Jules support code resides) is here, http://www.softcomp.com/haskell/wallfollow/thermostat.tar.gz Reactive.hs is where most of the interesting support routines live, including 'runReactor' We know Reactive is a bit of the cutting edge and everyone is busy hacking (in the good sense) but any help would be greatly appreciated. Any docs or papers you deem appropriate would be greatly appreciated also. We've been to the standard places .. Colin's site, Less Meat .., Reactive Mailing list, Haskell site, Frob, Fran, Fr _fill-in-the-blank_ etc. I'm hoping we simply made some silly mistake cause by our tenuous understanding of Reactive. Could this be the 'lazy pattern matching' issue? (An example of this with a server/client example was given in Gentle Intro to Haskell which wouldn't work until it was 'primed' by a lazy pattern match. If it would be more appropriate we can try to convert it to Colins' style. Any help greatly appreciated, Tom --------- Thermostat / Furnace Controller --------- module Main where import System.IO -- Jules Reactive import Deus.Reactive import Data.Time.Clock --import Data.Time.Calendar --import Data.Time.Format ---------------------------------------------- constFun :: Double -> UTCTime -> Double constFun constval trash = constval constB :: Double -> Behaviour Double constB value = timeFunction (constFun value) ---------------------------------------------- furnaceUpdate :: Behaviour Double -> Event Int -> Behaviour Double furnaceUpdate furnace ticker = (switcher (constB 25.0) (fmap constB (accumE 25.0 (snapshotWith (\watts ticker -> (\temp -> temp+(watts/100.0))) furnace ticker)))) -------------------------------------------------------------------- controllerUpdate :: Behaviour Double -> Event Int -> Behaviour Double controllerUpdate temp ticker = (switcher (constB 0.0) (fmap constB (snapshotWith (\temp tick -> (600.0 - temp) / 1000.0) temp ticker))) ---------------------------------------------------------------- furnaceMain :: Event Int -> Event (IO ()) furnaceMain ticker = let watts = (controllerUpdate temp ticker) temp = (furnaceUpdate watts ticker) in fmap (\result -> putStrLn $ "Temp -> " ++ show result) (snapshotWith (\t tick -> "\n" ++ show t) temp ticker) ---------------------------------------------------------------- ---------- -- Main -- ---------- main = do --hSetBuffering stdin NoBuffering --hSetBuffering stdout NoBuffering ticker <- timewiseIterate 10000 (+1) 0 runReactor (furnaceMain ticker) putStrLn "Done .."