2009/3/29 Freddie Manners
<f.manners@gmail.com>
Digging around with the commented query -- that a "pure (string)" is getting delayed -- I've hit a rather fundamental problem: it seems Event doesn't obey the Monad laws. I don't know whether this is a known issue or whether I'm being plain stupid, but this:--
module Main
where
import FRP.Reactive
import FRP.Reactive.LegacyAdapters
import Control.Concurrent
import Control.Applicative
import Control.Monad
import Data.Monoid
import Data.Maybe
main = do
clock <- makeClock
(sink, evnt) <- makeEvent clock
forkIO . sequence_ $ repeat (getLine >>= sink)
adaptE . fmap putStrLn $ (pure "A Line!" `mappend` evnt)
-- adaptE . fmap putStrLn $ (pure "A Line!" `mappend` (evnt >>= return))
and the same with the penultimate line commented instead of the last, appear to have different behaviours: in the version shown, "A Line!" is printed when the program starts; and in the other, this is delayed until after the first line is read (but before it is printed).
Should this happen?
Freddie Manners