Trex

[Ross Paterson]

On Fri, Jan 10, 2003 at 12:50:14PM +0000, Stephen Eldridge wrote:
> Using version Nov 2002 in Windows XP I find that import Trex gives me
> 
> Reading file "c:\progra~1\hugs98\lib\hugs\Trex.hs":
> ERROR "c:\progra~1\hugs98\lib\hugs\Trex.hs" - Illegal export of a lone data 
> cons
> tructor "EmptyRec"
> 
> This can be cured by removing the export of EmptyRec from Trex.hs
> but I don't think this should be necessary.

Exporting a constructor wasn't legal Haskell, and now Hugs implements
this restriction.  I think the problem is that EmptyRec isn't a real
constructor (it has type Rec EmptyRow, not Rec r), and the fix should
be to add

	emptyRec = EmptyRec

and export that instead of EmptyRec (and maybe change the Show instance
to match).