On Feb 6, 2008 10:04 AM, Luke Palmer <[EMAIL PROTECTED]> wrote: > How about: > > inv m = do > success <- (m >> return True) `mplus` return False > if success then mzero else return ()
Prelude Control.Monad> inv [] [()] Prelude Control.Monad> inv [10] [()] -- Felipe. _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
