[Haskell-cafe] Re: 2008-10-12 Hackage status with GHC 6.10 release candidate

Don Stewart dons at galois.com
Thu Oct 16 16:55:01 EDT 2008

> Simon Marlow wrote:
> >wren ng thornton wrote:
> >>Simon Marlow wrote:
> >>>Don Stewart wrote:
> >>>>     * GHC.Prim was moved,
> >>>
> >>>Nobody should be importing GHC.Prim, use GHC.Exts instead.
> >>
> >>
> >>This is oft declared, but as things stand I don't think it's a tenable 
> >>position. If someone's bothering to dig as far as GHC.Exts then it's 
> >>very likely they're trying to optimize numeric computations and for 
> >>that there are a number of functions in GHC.Prim which are essential, 
> >>in particular the fast conversion functions for numeric types[1]. If 
> >>those were moved to GHC.Exts then I think many people would be more 
> >>inclined to heed the advice.
> >
> >GHC.Exts re-exports the whole of GHC.Prim.  There's no reason to import 
> >GHC.Prim at all.  Admittedly this isn't immediately obvious from the 
> >documentation, but it is there.  Hopefully in the future we can improve 
> >Haddock so that it'll be able to paste in the whole of GHC.Prim into the 
> >GHC.Exts documentation, and we can then hide GHC.Prim.
> On more recent checking that seems to be the case, however I do recall 
> having issues with it in the past. Seems to work on 6.6 too so I'll 
> switch my stuff over.
> FWIW, if you explicitly re-export the entities by name Haddock will 
> paste them in (though that's a lot of copying in the export list).

Topic added to the wiki,


I'm glad we know how to handle the majority of migration issues
prior to the release. This is a first :)

-- Don

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