On Mon, Oct 07, 2013 at 06:22:33PM +0100, Tom Ellis wrote: > On Mon, Oct 07, 2013 at 07:14:44PM +0200, Niklas Haas wrote: > > On Mon, 7 Oct 2013 10:40:13 +0100, Tom Ellis > > <tom-lists-haskell-cafe-2...@jaguarpaw.co.uk> wrote: > > > I introduce a very simple extension to the Lens datatype from Control.Lens > > > that allows it to work with Arrows: > > > > > > https://gist.github.com/tomjaguarpaw/6865080 > > > > The reason we don't tend to have combinators like ‘view’ or ‘over’ > > generalized in their return profunctor like that is because you very > > quickly run into type ambiguity issues. > > Perhaps I didn't explain clearly what I am asking for. The crux of the > issue is whether it is possible *at all* to write the function > > overArr :: Arrow arr => Lens s t a b -> arr a b -> arr s t > > not whether it should be merged with over.
Edward Kmett has answered in the affirmative, which pleases me greatly! http://www.reddit.com/r/haskell/comments/1nwetz/lenses_that_work_with_arrows/ccmtfkj _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe