Exporting 0ary Constructors

Ross Paterson ross@soi.city.ac.uk
Mon, 7 Jul 2003 10:27:19 +0100


On Mon, Jul 07, 2003 at 01:56:22PM +0530, Arun Kumar S Jadhav wrote:
> 	With the previous release of hugs (hugs98 - Feb 2000) I could
> export 0ary data constructor functions.
> E.g
> 	data SplitOpt = EDGE_SPLIT | SIMP_GRAPH
> 	        deriving (Eq)
> and I could export EDGE_SPLIT and SIMP_GRAPH.
> 	But with latest release (hugs98 - Nov 2002) I get error message
> which essentially means I cannot export EDGE_SPLIT or SIMP_GRAPH.
> 	How to overcome this?

The old behaviour was a bug -- Haskell 98 doesn't permit exporting
constructors by themselves.  You can export

	SplitOpt(EDGE_SPLIT)

but not EDGE_SPLIT without SplitOpt.