MODULE Gap18SetCaseLabels;
(* NOT standard Modula-2: CASE requires an ordinal selector; gm2 allows
   set-typed CASE labels.  Class: gm2-ext.
   Corpus: bitset5.
   V3: not supported yet. *)
VAR b : BITSET;
BEGIN
  b := {1, 2};
  CASE b OF
  {}    : |
  {1, 2}: 
  END
END Gap18SetCaseLabels.