// returns number of changes
static int cset(Concept c, O... values) ctex {
  if (c == null) ret 0;
  int changes = 0;
  values = expandParams(c.getClass(), values);
  warnIfOddCount(values);
  for (int i = 0; i+1 < l(values); i += 2)
    if (_csetField(c, (S) values[i], values[i+1])) ++changes;
  ret changes;
}