[cvs-nhc98] Change internal representation of export decls.

[Malcolm Wallace]

malcolm: Wed Aug  8 16:58:19 CEST 2001

Update of /usr/src/master/nhc/src/compiler98
In directory hinken:/tmp/cvs-serv16932

Modified Files:
	AuxFile.hs AuxLabelAST.hs Need.hs Parse2.hs PreImport.hs 
	PrettySyntax.hs Syntax.hs TraceTrans.hs 
Log Message:
Change internal representation of export decls.

  * Previously, the two cases
        module M where
        module M () where
    were not distinguished!
    The former should export everything, the latter nothing.

  * In the old representation both cases were [] :: [Export id].

  * In the new representation :: Maybe [Export id],
    Nothing means nothing, and Just [] means everything.
    (Just [...] gives an explicit list of export decls much as before.)