[Haskell-beginners] Logging in Haskell

Hi community, As my Haskell programs grow above 100 lines of code, I feel the necessity to trace the execution of them more closely. In imperative languages one may use logging facilities for checking intermediary values of variables, the execution flow, etc. How this usually handled in Haskell (I bet that despite the fact that in Haskell it is relatively easier to write bug-free and checked code, the industrial systems still need some logging being done)? Regards, Sergey