Hello, I have a somewhat complicated calculation programmed in Haskell. This calculation is coded without using monads. I want to also produce a report describing the details of this calculation for each particular set of inputs. e.g. Number of hours worked = 100. Gross pay per hour = 50. Total gross = 100 * 50 = 500. etc. But about 20 times more complicated than the above. Naturally I need to write functions to produce the above description/report as it should be well presented. Only showing the important parts of the calculation in a sensible order. But I am wondering how to combine the generation of the report with the calculation together. I think if I add the report generating functions into the calculation functions, it will make them twice as messy, and they are already complicated enough. On the other hand replicating the calculation source code twice, once without reporting and once without seems bad. Any suggestions on how to handle this? Rene.