instance export decls

[Serge D. Mechveliani]

On Fri, May 02, 2008 at 03:03:14PM -0700, John Meacham wrote:
> On Thu, May 01, 2008 at 03:21:11PM +0100, Simon Peyton-Jones wrote:
> > Indeed! I think it'd be good to allow type signatures, including
> > instance signatures, in export lists
> 
> The problem with instance signatures is that it would give the
> impression that it would be possible to _not_ export an instance, and it
> wouldn't make explicit the fact that the instances of all modules it
> depends on are also exported. 

Yes. 
Still, listing instances in export makes it possible not to look through
all the source module in order to recall the instances defined in this 
module.

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Mechveliani