// params = input, output, input, output, ...
svoid mapLike testFunctionValues_struct(S function, O... params) {
  for (int i = 0; i+1 < l(params); i += 2) {
    O in = params[i], expected = params[i+1];
    print(function + "(" + struct(in) + ")");
    assertEqualsVerbose_struct(expected, callF(function, in));
  }
}