Re: [Haskell-cafe] fclabels 0.5
just what I was looking for, thanks! 2012/8/20 Erik Hesselink hessel...@gmail.com: Untested, but this should be about right: osi (Bij f b) = iso (Bij b f) Erik On Mon, Aug 20, 2012 at 2:35 PM, Sergey Mironov ier...@gmail.com wrote: Hi. I'm porting old code, which uses fclabels 0.5. Old fclabels define Iso typeclass as follows: class Iso f where iso :: a :-: b - f a - f b iso (Lens a b) = osi (b - a) osi :: a :-: b - f b - f a osi (Lens a b) = iso (b - a) Newer one defines iso: class Iso (~) f where iso :: Bijection (~) a b - f a ~ f b instance Arrow (~) = Iso (~) (Lens (~) f) where iso bi = arr ((\a - lens (fw bi . _get a) (_set a . first (bw bi))) . unLens) instance Arrow (~) = Iso (~) (Bijection (~) a) where iso = arr . (.) but no osi. I'm not a guru in categories, can you help me define osi? Thanks Sergey. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] fclabels 0.5
Hi. I'm porting old code, which uses fclabels 0.5. Old fclabels define Iso typeclass as follows: class Iso f where iso :: a :-: b - f a - f b iso (Lens a b) = osi (b - a) osi :: a :-: b - f b - f a osi (Lens a b) = iso (b - a) Newer one defines iso: class Iso (~) f where iso :: Bijection (~) a b - f a ~ f b instance Arrow (~) = Iso (~) (Lens (~) f) where iso bi = arr ((\a - lens (fw bi . _get a) (_set a . first (bw bi))) . unLens) instance Arrow (~) = Iso (~) (Bijection (~) a) where iso = arr . (.) but no osi. I'm not a guru in categories, can you help me define osi? Thanks Sergey. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] fclabels 0.5
Untested, but this should be about right: osi (Bij f b) = iso (Bij b f) Erik On Mon, Aug 20, 2012 at 2:35 PM, Sergey Mironov ier...@gmail.com wrote: Hi. I'm porting old code, which uses fclabels 0.5. Old fclabels define Iso typeclass as follows: class Iso f where iso :: a :-: b - f a - f b iso (Lens a b) = osi (b - a) osi :: a :-: b - f b - f a osi (Lens a b) = iso (b - a) Newer one defines iso: class Iso (~) f where iso :: Bijection (~) a b - f a ~ f b instance Arrow (~) = Iso (~) (Lens (~) f) where iso bi = arr ((\a - lens (fw bi . _get a) (_set a . first (bw bi))) . unLens) instance Arrow (~) = Iso (~) (Bijection (~) a) where iso = arr . (.) but no osi. I'm not a guru in categories, can you help me define osi? Thanks Sergey. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
