In Haskell you don't ever take the `head` of a list, because `head` is an evil non-total function. Instead you pattern-match the list: in one branch, the head i

In Haskell you don't ever take the `head` of a list, because `head` is an evil non-total function. Instead you pattern-match the list: in one branch, the head is given to you for free; in the other branch, there's no head at all.