I'm confused too. I'd welcome clarification from the Haskell Prime folk. S
-----Original Message----- From: Serge D. Mechveliani [mailto:mech...@botik.ru] Sent: 23 December 2011 17:36 To: Simon Peyton-Jones Subject: Re: 7.4.1-pre: Show & Integral On Thu, Dec 22, 2011 at 08:14:54PM +0000, Simon Peyton-Jones wrote: > | 2011/12/22 Edward Kmett <ekm...@gmail.com>: > | > The change, however, was a deliberate _break_ with the standard that > | > passed through the library review process a few months ago, and is now > | > making its way out into the wild. > | > | Is it reasonable to enquire how many standard-compliant implementations > | of Haskell there are? > > Just to be clear, the change IS the standard. GHC has to change to be > compliant. > At least that's how I understand it. I am confused. I am looking now at the on-line specification of Haskell-2010, 6.3 Standard Haskell Classes. It shows that Integral includes Show: Eq Show \ / Num | Enum Real \ | Integral This is also visible in the further standard class declarations in this chapter. Hence, for `x :: Integral a => a' it is correct to write (shows x ""). And ghc-7.4.0.20111219 does not allow this. So, ghc-7.4.0.20111219 breaks the 2010 standard. Now, Edward Kmett writes that this break is done deliberately. Am I missing something? I witness this for the first time: that GHC deliberately breaks the current Haskell standard. Probably, many people (as myself) dislike this point of the standard. Well, they can write a dummy Show implementation for their type T: showsPrec _ _ = showString "(<t> :: T)", and wait for an improved standard, say, Haskell-II -- ? Regards, ------ Sergei mech...@botik.ru _______________________________________________ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime