On Tue, Mar 02, 2010 at 08:20:30PM +0100, Sean Leather wrote: > There are numerous threads on the Haskell Café involving rewriting, > refactoring, refining, and in general improving code (for some definition of > improve). I am interested in seeing examples of how Haskell code can be > rewritten to make it better. Some general examples are:
One handy manual transformation is trying to do more checks on the typechecker. GADT's + phantom types are very useful! > x >>= return . f > --> > fmap f x > or > f <$> x -- requires importing Control.Applicative > > I think the right-hand side (RHS) is more concise and simpler. The types > here do change: the type constructor has a Monad constraint in the left-hand > side and a Functor constraint in the RHS. Types that are Monad instances are > generally also Functor instances, so this is often possible. I'm convinced > the semantics are preserved, though I haven't proven it. Yes, they are the same, always. -- Felipe. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
