[Haskell-cafe] Re: what does @ mean?.....

Achim Schneider wrote:

zeroIf :: MonadPlus m => (a -> Bool) -> m a -> m a zeroIf f m = m >>= (\nz -> if f nz then mzero else m)

zeroZero :: (MonadPlus m, Num a) => m a -> m a zeroZero = zeroIf (==0)

makes it interesting again as you can't construct a Just value with it.

d'oh. return nz. /me hides under a monad.