Re: [Haskell-cafe] Object oriented haskell.

Recently, on LtU: http://lambda-the-ultimate.org/node/4951 Most relevantly: https://ghc.haskell.org/trac/ghc/wiki/Records/DeclaredOverloadedRecordFields... – Kyle Marek-Spartz On May 15, 2014, 12:38:29 PM, silvio wrote: Hi Haskell, I've been wondering if (.) is so cool in other languages why can't we make it even cooler in haskell. And went on to implement such a (.) based on multiparameter type classes and type families. type family Output object action class Action object action where (.) :: object -> action -> Output object action I'm not sure if this has been done before like this but i didn't find anything. I used Map as an example, and here is what I ended up with:

:m -Prelude import Prelude hiding ((.)) import Object import Object.Example import Data.Map hiding (size) let m = empty . [ 'f' := Just 1, 'o' := Just 2, 'o' := Nothing ] m fromList [('f',Just 1),('o',Nothing)] m . 'f' Just 1 m . size 2

I also have a pretty cool (almost) solution to the name collision problem. Visit the project homepage for a more thorough explanation. https://github.com/yokto/object And to those who gonna hate on me because they like the (.) as function composition I have only this to say. type instance Output (b -> c) (a -> b') = (a -> c) instance (b ~ b') => Action (b -> c) (a -> b') where f . g = f Prelude.. g Have fun, Silvio _______________________________________________ Haskell-Cafe mailing list mailto:Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe