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
  if __ghdl_bool_type'(a > 5) then
    return a +# 1;
  else
    return a -# 1;
  end if;
end;