// Use like this: renderVars(+x, +y)
// Or like this: renderVars SomeID(+x, +y)
sS mapMethodLike renderVarsWithoutNulls(O... params) {
  new LS l;
  int i = 0;
  if (odd(l(params))) {
    l.add(strOrNull(first(params)));
    ++i;
  }
  for (; i+1 < l(params); i += 2)
    if (params[i] != null && params[i+1] != null)
      l.add(params[i] + "=" + params[i+1]);
  ret trim(joinWithComma(l));
}