Functional Programming Doesn't Work (and what to do about it)

Functional programming works just fine. If you want to take two isolated functions and make them behave in some complicated manner depending on how often one or both are called, simply refactor them into the state monad. I.e., replace f: a -> a with f: a -> State a, and do the same for g. This is likely to break stuff. In C, good luck figuring out what might be broken as a result. In a pure functional language, you…

Imagine you've implemented a large program in a purely functional way. All the data is properly threaded in and out of functions, and there are no truly destructive updates to speak of. Now pick the two lowest-level and most isolated functions in the entire codebase. They're used all over the place, but are never called from the same modules. Now make these dependent on each other: function A behaves differently depending on the number of times function B has been…

Flagged for bait-y title. This is one of those articles that contradicts its title in the first few sentences. Better titles: "Purely functional programming doesn't work" or "sometimes functional programming doesn't work, but I'm still a functional programming advocate".