static int smartIndexOfSpacedDash(L<S> x, int i) {
  outer: for (i |= 1; i+3 <= l(x); i += 2) {
    if (eq(x.get(i+1), "-") && nempty(x.get(i)) && nempty(x.get(i+2)))
      ret i;
  }
  ret l(x);
}