// accepts a string as predicate (then compares with "eq")
static int gSearchIdx(O predicate) {
  ret gSearchIdx(predicate, 0);
}

static int gSearchIdx(O predicate, int startIdx) {
  ret gSearchIdx(gLog(), predicate, startIdx);
}

static int gSearchIdx(L<S> log, O predicate, int startIdx) {
  if (predicate == null) ret -1;
  if (predicate instanceof S) {
    final S _s = (S) predicate;
    predicate = func(S s) { eq(s, _s) };
  }
  
  for (int i = l(log)-startIdx-1; i >= 0; i--)
    if (isTrue(callF(predicate, log.get(i))))
      ret i;
  ret -1;
}