[Haskell-cafe] Why isn't ArrowChoice a parent of of ArrowApply?

2013-06-20 Thread Petr Pudlák
In Control.Arrow we have: |leftApp ::ArrowApply a = a b c - a (Either b d) (Either c d)| Any instance of |ArrowApply| can be made into an instance of |ArrowChoice| by defining |left = leftApp|. So why isn't |ArrowChoice| a parent of |ArrowApply|? Best regards, Petr

Re: [Haskell-cafe] Why isn't ArrowChoice a parent of of ArrowApply?

2013-06-20 Thread Ross Paterson
On Thu, Jun 20, 2013 at 09:02:48AM +0200, Petr Pudlák wrote: In Control.Arrow we have: leftApp :: ArrowApply a = a b c - a (Either b d) (Either c d) Any instance of ArrowApply can be made into an instance of ArrowChoice by defining left = leftApp. So why isn't ArrowChoice a