Re: [Haskell-beginners] how to skip pattern match error when applying a mapM_

If e.g. 'gamma' is 'Nothing', then the following expressions aren't evaluated and the whole "do-block" returns 'Nothing'.

I just saw that 'row' isn't operating in the 'Maybe' monad but in the 'IO' monad, so this wont work. I don't know if 'row' contains any side effects that should also be executed if the returned 'Maybe' is 'Nothing', if this isn't the case, then you might be able to switch the return type of 'row' from 'IO (Maybe ...)' to 'Maybe (IO ...)' and then you could get the described behaviour for 'Maybe'. Greetings, Daniel