On Sat, Jul 10 2010, wren ng thornton wrote: [...]
Yes, you can add multiple dependencies. The syntax is to use , after the first |.
While having eight parameters is surely a desperate need for refactoring, there are times when you'd want multiple dependencies. For example, you can say
class F a b | a -> b, b -> a where...
to express a bijective function on types (that is, for every pair of A and B, if you know one of them then you know what the other must be uniquely).
I know i should read the relevant articles, but how would one express such a bijection using type families? TIA, jao -- You err by thinking simplicity and elegance are mostly cosmetic. Simplicity and elegance are overwhelmingly practical virtues. - William D Clinger, comp.lang.scheme