Hello, The type of the monadic bind function in the Monad class is Monad m => m a -> (a -> m b) -> m b Now, would it be possible to create a monad with a slightly stricter type, like StrictMonat m => m a -> (a -> m a) -> m a and, accepting that all steps of the computation would be bound to operate on the same type, would this be without any undesirable implications? For the sake of understanding monads better, I tried to write several custom monads which may or may not be useful. Among those were: * The Tracker Monad - tracks every result of every step of the sequential computation in a (normal, stricly typed) list inside of the monad * The Goto Monad - sequential computation that allows restarts of the computation at arbitrarily set labels within it But Haskell doesn't like those. Rightly so, because the bind function would have the stricter type mentioned above. [Otherwise the Tracker monad would have to store values of different types in its list and the Goto monad would encounter restarts at labels that process different types of the value than what has been computed so far. Both doesn't make sense.] I still have to prove wether those two monads follow the monadic laws at all, but that's part of my exercise. But let's say they follow the laws (I'm pretty sure that at least the Tracker monad does), is there anything else that would prevent the stricter typing from being legal or useful? Maybe I'm missing something simple. And would I still be able to use Haskell's "do" syntax? My first guess is yes, because it really just seems to translate into normal syntax. Thanks, Julien