> Is still don't see why you need it. I have the feeling that you abuse Num > and Fractional classes just for re-use of symbols like (*) and (/) in an
Maybe. It is true that I had the same feeling when first using the CG language: when v and u are (4D) vectors, then -u, u+v and u-v make perfect sense, but u*v, u/v, abs u, signum u, fromInteger u, sin u, etc, don't. In CG this is just solved by applying these operators componentwise. So when u=[u1 u2], then (abs u) = [(abs u1) (abs u2)]. Maybe not really correct in the mathematical sense, but it works fine in practice. It feels silly to invent new operators and names for all of these; the code looks weird, and every function in Num, Fractional, and Floating can be lifted fine into this componentwise scheme. I just "invented" extra operators (dot, cross, mul) to specify dot product, cross product, matrix/vector and matrix/matrix multiplication etc. These clearly do not fit in the numeric classes. Anyway, I started from scratch again, and all is working fine now. As a Haskell newbie, I face this a lot: it seems I'm really stuck with something, wanting to give up on Haskell, and then next day when I start my code from scratch, then it suddenly works fine in a much more elegant way. Maybe I should always do that before asking silly questions here ;) And I should checkin every version that does NOT work, so I can see what went wrong. Now I had them same when digesting C++ templates, so it's not really related to Haskell... Thanks, Peter PS: IMHO it's also a bit problematic the way the numeric classes in Haskell are defined. It would have been nicer if it followed mathematics a bit more, as it seems to be done in the upcoming Sun Fortress language. This is just a *feeling* I'm having by quickly reading the Fortress language specs, so I might be very very wrong :) No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.484 / Virus Database: 269.12.1/965 - Release Date: 21/08/2007 16:02 _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe