TYPE __ghdl_index_type IS UNSIGNED (32);
TYPE __ghdl_bool_type IS BOOLEAN {false, true};

PUBLIC FUNCTION main (a : __ghdl_index_type) RETURN __ghdl_index_type
DECLARE
BEGIN
  CASE a IS
    WHEN 1 =>
      RETURN 2;
    WHEN 3 ... 5 =>
      RETURN 1;
    WHEN DEFAULT =>
      RETURN 0;
  END CASE;
END;