But there is not a way to easily say (in Haskell) "type A is everything that type B is plus these other things here ...". Haskell is not an OO language.
This captures what I had in mind. Using compound types seems ok but I'd still need to do some mechanical stuff if I had to provide a function that works on the compound type which is actually defined for a component type. If I understand you right .. you'd build a 'Man' type and 'Woman' type by using a 'Person' type. Lets say, there is a function called getName that is Person -> String I'd have to mechanically define a function getName :: Man -> String - that extracts the person inside and calls getName on it - did I understand it right? Or would you typically write extract functions that'll return the components and then the user could call the method on the component? As in .... getPerson :: Man -> Person ... then call getName on that. How do you deal with situations like that?