Hi, Ömer Sinan Ağacan wrote:
One thing I'm not happy about my Haskell programs is, almost all of my programs have a monad transformer stack consisting MonadError, MonadIO and MonadState.
You can try to write most of your program in pure functions that are called from a few "main" functions in the monad. Or, if you need some but not all monadic actions in each function, you can use the following pattern: -- This helper function cannot cause monadic effects other than -- throwing errors. But it can be used in arbitrary monads that -- support throwing errors. helper :: MonadError MyError m => ... -> m ... helper = do ... -- Same but with only allowing IO, but other monadic actions other :: MonadIO m => ... -> m ... other = do ... -- we can use both functions in the same monad main = runMyStack $ do helper other This way, you have some control over what effects are allowed where. Tillmann