You would write something like List a = Cons a (List a) | Nil As :: doesn't start with a letter, it's infix by default. But basically a binary constructor. If

You would write something like List a = Cons a (List a) | Nil As :: doesn't start with a letter, it's infix by default. But basically a binary constructor. If you want to create the List [1,2,3] in the prefix notation you might be used to: ::(1,::(2,::(3,[])))