static S lineAroundToken(L<S> tok, int tokenIndex) {
  int i = tokenIndex, j = tokenIndex;
  while (i > 1 && !containsNewLine(get(tok, i-1)))
    i -= 2;
  while (j+2 < l(tok) && !containsNewLine(get(tok, j+1)))
    j += 2;
  ret afterLineBreak(get(tok, i-1)) + joinSubList(tok, i, j+1) + beforeLineBreak(get(tok, j+1));
}