Brent Yorgey schrieb: > On Mon, Dec 22, 2008 at 06:19:07PM +0100, Peter Padawitz wrote: >> I'd like to define a monad Set for types in the class Eq. But how can the >> arguments of Set be constrained when Set is defined as an instance of >> Monad? instance Eq a => Monad Set where ... obviously cannot work. >> >> Is there a standard update function for fields in data types, something >> that OO programmers do with assignments like obj.attr := value ? >> >> Peter >> > > Note there is already a package on Hackage to do exactly this, rmonad. > > http://hackage.haskell.org/cgi-bin/hackage-scripts/package/rmonad
And also http://hackage.haskell.org/cgi-bin/hackage-scripts/package/data-accessor _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe