// Convert all spacing to a single space, so everything's neat & on one line.
static L<S> simpleSpaces(L<S> tok) {
  tok = cloneList(tok);
  for (int i = 0; i < l(tok); i += 2)
    tok.set(i, tok.get(i).equals("") ? "" : " ");
  ret tok;
}

static S simpleSpaces(S s) {
  ret join(simpleSpaces(nlTok(s)));
}