On Wed, 11 Jul 2007, Jules Bean wrote: > Now, supposing we have a library function which takes a callback. As > an example, suppose we have a library function which reads in a file > and calls our callback once on each line. A typical type might look > like: > > forEachLine :: Handle -> (String -> IO ()) -> IO () > > We have to provide a callback in the IO monad. But what if we don't > want to work in the IO monad? What if we are working in, for example, > a custom state monad of our own?
What about writing a function with signature forEachLine :: MonadIO io => Handle -> (String -> io ()) -> IO () ? _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
