2009/1/23 Olex P <hoknamahn@gmail.com>

Hello Haskellers!
It's probably a simple question but I can't find a proper solution...
Suppose we have a class Vector which overloads (+) operation. I'd like to represent a Matrix data type as a set of vectors:

data Matrix3 = M3 !Vector3 !Vector3 !Vector3

In this case (+) for matrices could be implemented as:

(M3 r11 r12 r13) + (M3 r21 r22 r23) = M3 (r11 + r21) (r12 + r22) (r13 + r23)

But GHC says about ambiguous occurrence. I don't understand why because it's should be pretty clear that rows are vectors and (+) has to be vector type as well. I could use Vector.+ instead but it doesn't look good.
Probably I'm missing something. Any ideas?

I'm am seeing an image. It's a... a Vector class, with an operation (+). Oh, he's with another one though. It's the Num class. Oh they're fighting over the (+). Vector is trying to take it from Num, but Num isn't letting go.

Why doesn't Vector see that there is a whole pile of operations neglected in the corner, like (^+^), (.+.). He just really wants that (+), huh...

Luke