Imagine the following data type: data Person = Child { childAge :: Int, school :: School } | Adult { adultAge :: Int, job :: Job } Both the alternatives share an "age" field, but in order to access it we are obliged to match all the constructors: personAge :: Person -> Int personAge (Child {childAge = age}) = age personAge (Adult {adultAge = age}) = age Is there a way to define a common field in a data type (somehow like inheritance in the OOP world)? It would be practical if we could define "age :: Int" as a common field and do something like: personAge (_ {age = age}) = age An alternative solution could be extracting the varying fields in a different type: data WorkingPerson = Child School | Adult Job data Person = Person { age :: Int, workingPerson :: WorkingPerson } Or to make Person a type class (which would probably require existential types in order to be useful). But the first one looks simpler and more natural. Does this feature exist (maybe in other forms) and, if not, is there a reason? Would it make sense to have a GHC extension (or even to make a Template Haskell hack) for this feature?