Amy,
Quaternion.hs:6:13: Ambiguous occurrence `*' It could refer to either `Main.*', defined at Quaternion.hs:5:0 or `Prelude.*', imported from Prelude
... and lots more messages like that. I understand roughly what the message means, but I don't know how to tell it that when I use "*" within the definition, I just want ordinary multiplication. Thanks in advance for any
You're redefining (*) in Main, which creates the ambiguity, which is the problem. One alternative is, instead of creating a new ambiguous (*), is use the existing one, and make it apply to your type. The existing (*) belongs to the typeclass Num. You can make your type an instance of Num, with your definition of (*): instance Num (Quaternion a) where q1 * q2 = ... q1 + q2 = undefined -- or, better, a valid definition q1 - q2 = undefined ... You'll find that this cascades into requiring you to define a handful of other class functions (+, -, negate, abs, signum, fromInteger) and you'll need Eq and Show instances. You can derive the latter, and you can give trivial (undefined or error) definitions for, say, negate if you won't be using it. Hope this helps. John