Proposal: remove datatype contexts from base

[Simon Peyton-Jones]

I'd love to do this, but it'd mean that GHC wouldn't conform to Haskell 98 unless we shipped two versions of the libraries, which seems overkill.  

Do you think that's acceptable? I think it probably is.  We can just record it as a shortcoming of GHC, but it's one that no one will care about.

Simon

| -----Original Message-----
| From: libraries-bounces at haskell.org [mailto:libraries-bounces at haskell.org] On Behalf
| Of Ross Paterson
| Sent: 24 May 2011 15:08
| To: libraries at haskell.org
| Subject: Proposal: remove datatype contexts from base
| 
| The Haskell' committee decided to remove datatype contexts from the language:
| 
| http://www.haskell.org/pipermail/haskell-prime/2011-January/003335.html
| 
| (though this doesn't seem to be in the Report yet.)
| 
| In the base package there are 4 of these:
| 
|   Data/Complex.hs:data (RealFloat a) => Complex a
|   GHC/Arr.lhs:data Ix i => Array i e
|   GHC/Real.lhs:data  (Integral a)      => Ratio a = !a :% !a  deriving (Eq)
|   Control/Arrow.hs:newtype ArrowApply a => ArrowMonad a b = ArrowMonad (a () b)
| 
| As far as I know, removing them won't break any code that compiles now,
| so let's do it.
| 
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