I would pose a harsher criticism against Haskell then the one posed in this article. I believe that logical relations are a better foundation for declarative programming then functions. As such, even when it comes to declarative programming I'd much rather use Prolog then Haskell.

Fortunately, there are Prolog systems compatible with the JVM and most scheme environments so you can embed Prolog in Clojure and Scheme for declarative programming tasks.