[valenterry]

> Static types, algebraic data types, making illegal states unrepresentable: the functional programming tradition has developed extraordinary tools for reasoning about programs

Looks like the term "functional programming" has been watered down so much that now it is as useful as OOP: not at all.

Look, what matters is pure functional programming. It's about referential transparency, which means managing effects and reason about code in a similar way you can do with math. Static typing is very nice but orthogonal, ADT and making illegal states unrepresentable are good things, but all orthogonal.