Re: [Haskell-cafe] what I learnt from my first serious haskell programm

David House wrote:

On 19/03/07, Fawzi Mohamed wrote:

...

Vectors don't act like numbers, a vector space is not a field, even if they have some common operations.

As I said in my previous email, this is because Num is too big. We need to split it down, but there's no sane way of doing this without your average numeric function needing about a thousand different constraints on it. Type class synonyms [1] look promising, but no-one's implemented them yet AFAIK.

[1]: http://repetae.net/john/recent/out/classalias.html

I might missing something fundamental but what is the advantage of a class alias with respect to multiple inheritance? i.e. class alias FooBar a = (Foo a, Bar a) vs class (Foo a, Bar a) => FooBar can an alias be implemented a posteriory without modifying the code of FooBar? because what one really wants to do is to split Num even if Num is not splitted, but this would create problems with type inference... Fawzi