% $Id: RMember.oz,v 1.1 2007/11/30 20:05:55 leavens Exp leavens $
declare
proc {RMember ?X ?Ls}
   local E Es in
      Ls=E|Es
      choice
         X=E
      [] {RMember X Es}
      end
   end
end

proc {RMember2 ?X ?Ls}
   choice
      Ls=X|_
   [] local Es in
         Ls=_|Es
         {RMember2 X Es}
      end
   end
end