On 09/05/12 03:49, MigMit wrote: > On 8 May 2012, at 21:42, Felipe Almeida Lessa wrote: > >> On Tue, May 8, 2012 at 2:36 PM, MigMit <miguelim...@yandex.ru> wrote: >>> Hi café, a quick question. >>> >>> Is there a somewhat standard class like this: >>> >>> class Something c where >>> unit :: c () () >>> pair :: c x y -> c u v -> c (x, u) (y, v) >>> >>> ? >>> >>> I'm using it heavily in my current project, but I don't want to repeat >>> somebody else's work, and it seems general enough to be defined somewhere; >>> but my quick search on Hackage didn't reveal anything. >>> >>> I know about arrows; this, however, is something more general, and it's >>> instances aren't always arrows. >> Are you aware of generalized arrows [1]? It's still a lot more than >> your Something, though. > I've heard of them, but some instances of my Something class aren't > categories either, which rules out GArrows too. > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe data-lens has something similar (Tensor):
http://hackage.haskell.org/packages/archive/data-lens/2.10.0/doc/html/Control-Category-Product.html -- Tony Morris http://tmorris.net/ _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
