| Is there a more verbose, newbie-friendly documentation that will answer | questions like, | "Suppose I have a function foo :: String -> String. How does GHC | represent the type of this function?" We don't have verbose newbie-friendly documentation, I'm afraid. But GHC is an open-source compiler, and one thing that people can very helpfully contribute is precisely this sort of documentation. After all, a typical sequence is - "I wish I knew X" - Much reading of code, and consultation of the mailing lists - "Now I know X (to some degree)" It would be great to add - Add documentation about X to the Commentary The commentary is a wiki:, so anyone can add to it. We're happy to review draft changes. Meanwhile, to your point, the code you need is in compiler/types/TypeRep, which contains tha (very small) data type that represents types. Simon