I'm trying to learn Haskell (for fun, of course). My only previous experience with the functional programming paradigm was playing around with Scheme a bit. I was nodding my head to "A Gentle Introduction to Haskell" until I got to this, from section 2.2, User-Defined Types:

"Note that the type of the binary data constructor Pt is a -> a -> Point a, ..."

This is from http://www.haskell.org/tutorial/goodies.html

Now, where the heck does this type come from, and what does it mean? Just a paragraph before, we learn that "-> is a type constructor: given two types t and u, t->u is the type of functions mapping elements of type t to elements of type u."

So Pt maps elements of "a -> a" to elements of "Point a"? Or does it map elements of "a" to elements of "a -> Point a"? How does either of these possibilities make any sense? Seems like it maps two elements of type "a" to a single element of type "Point a", no?

I tried the "just ignore and keep reading, hoping it will make sense later" technique, but the next section, 2.2.1, Recursive Types, defines the Branch type in a similarly baffling way. Hopefully, someone more knowledgeable here will be so kind as to clear this up for me.