I know it's been a while since this was published, but could you please check the latest issue about this? :P

approved some time ago

approved some time ago

too late now with 150 completions, it would be unfair to invalidate them :(

I don't understand why this would matter, mind explaining?

The tests only check for associativity. So addition is a valid answer.

Also see this solution. Anyway, why are we still using Haskell for theorem proving, when we already have Coq, Agda and Lean? ;-)

Those kata which teach practical skills are underated, I feel.

I don't think I'm mentally capable of completing this.

Sad this kata just died, hasn't had a solution in months. It could technically be approved with 5 ratings?

Get to know LambdaCase from your comment!

Fixed!

// BinOp has methods 'a()' and 'b()', both return 'Ast'
// UnOp has method 'n()' returning 'int'

a, b, n are fields not methods