This is an excellent illustration. I feel functional programming provides great tools and concept for a cohesive system (one with consistent requirements, which accomplishes a single thing, etc). But many programs you write involve parts that aren't very cohesive and trying to make them cohesive is far more work than just bolting on a case statement or similar things.

Parent currently downvoted without comments. Seems like a sad way to respond.

I feel like you might be missing the point. A case statement is not to be treated as something you bolt on as a hack. It is the right tool for the job the vast majority of the times. When you use case statements, you refine and reduce your state space. It makes code easier to understand. When you combine this with the idea of making illegal states unrepresentable, a case statement gives you an exhaustive listing of what could happen. Even a lot of Haskell programmers, after using things like the `maybe` function to eliminate Maybe types and things like `fmap` over Maybe, eventually find that using case expressions produces the clearest code even though it may be one line longer.

I really hope HN enforces a rule that a downvote must be accompanied by a reply.