[Haskell-cafe] Re: Nofib modifications

[Simon Marlow]

I'd do something like

#if defined(__nhc98__) || defined(YHC)
#define NO_MONOMORPHISM_RESTRICTION
#endif

#ifdef NO_MONOMORPHISM_RESTRICTION
powers :: [[Integer]]
#endif

just to make it quite clear what's going on.  (good comments would do just 
as well).

Cheers,
	Simon

Simon Peyton-Jones wrote:
> By all means apply a patch, I think.
> 
> Simon
> 
> | -----Original Message-----
> | From: haskell-cafe-bounces at haskell.org [mailto:haskell-cafe-bounces at haskell.org] On Behalf Of Neil Mitchell
> | Sent: 03 December 2007 17:34
> | To: Haskell Cafe
> | Cc: Simon Marlow; Malcolm Wallace; Duncan Coutts
> | Subject: [Haskell-cafe] Nofib modifications
> |
> | Hi,
> |
> | Some of the nofib suite are messed up by Yhc/nhc because of the
> | monomorphism restriction. Take imaginary/bernouilli as an example:
> |
> | powers = [2..] : map (zipWith (*) (head powers)) powers
> |
> | Hugs and GHC both see powers :: [[Integer]] and a CAF.
> |
> | Yhc (and nhc) both see powers :: (Enum a, Num a) => [[a]] and no CAF.
> |
> | This completely destroys the performance in Yhc/nhc. Since this is not
> | so much a performance aspect but a compiler bug, based on a feature
> | whose future in Haskell' is as yet unclear, perhaps it would be wise
> | to patch nofib to include an explicit type signature where this
> | matters. I am happy to send in a patch (or just apply it) - but I have
> | no idea who "maintains" the suite. I've CC'd those people who make
> | substantial use of the nofib suite.
> |
> | Thanks
> |
> | Neil
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