> But then you want ADTs, which aren't really functional. Pretty sure by ADTs, GP means "algebraic data types". These are very much functional, at least in the

> But then you want ADTs, which aren't really functional. Pretty sure by ADTs, GP means "algebraic data types". These are very much functional, at least in the sense that they're a standard feature of statically typed FP (at least I know of no such language that doesn't have them). ADT also sometimes stands for "abstract data type", which is something different. Although I wouldn't call them incompatible with FP either, Haskell typeclasses can express abstract data types, for example.