You can write functional code in Lisp. But Lisp isn't really a functional language. That is, you have to kind of fight the language to write non-functional code in Haskell. In Lisp, you don't.
So if you learn Lisp, you learn a language that transcends programming style. It's much more universal than Haskell.
So if you learn Lisp, you learn a language that transcends programming style. It's much more universal than Haskell.