--concrete RelativeTha of Relative = CatTha ** open ResTha in {
--
--  flags optimize=all_subs ;
--
--  lin
--
--    RelCl cl = {
--      s = \\t,a,p,_ => "such" ++ "that" ++ cl.s ! t ! a ! p ! ODir ; 
--      c = Nom
--      } ;
--
--    RelVP rp vp = {
--      s = \\t,ant,b,ag => 
--        let 
--          agr = case rp.a of {
--            RNoAg => ag ;
--            RAg a => a
--            } ;
--          cl = mkClause (rp.s ! RC Nom) agr vp
--        in
--        cl.s ! t ! ant ! b ! ODir ;
--      c = Nom
--      } ;
--
---- Pied piping: "at which we are looking". Stranding and empty
---- relative are defined in $ExtraTha.gf$ ("that we are looking at", 
---- "we are looking at").
--
--    RelSlash rp slash = {
--      s = \\t,a,p,_ => slash.c2 ++ rp.s ! RPrep ++ slash.s ! t ! a ! p ! ODir ;
--      c = Acc
--      } ;
--
--    FunRP p np rp = {
--      s = \\c => np.s ! Acc ++ p.s ++ rp.s ! RPrep ;
--      a = RAg np.a
--      } ;
--
--    IdRP = {
--      s = table {
--        RC Gen => "whose" ; 
--        RC _   => "that" ;
--        RPrep  => "which"
--        } ;
--      a = RNoAg
--      } ;
--
--}