static L<PairS> minusSignSectionPairs(S text) {

  LS lines = lines(text);

  L<Int> l = indicesOfStartingWithTrim(lines, "--");

  new L<PairS> out;

  // prelude

  if (nempty(l)) {

    S s = rtrim(lines(subList(lines, 0, first(l))));

    if (nempty(s))

      addPair(out, "", s);

  }

  for i over l: {

    int i1 = l.get(i);

    int i2 = or(get(l, i+1), l(lines));

    S heading = trim(lines.get(i1));

    int iHeading = 0;

    while (iHeading < l(heading) && heading.charAt(iHeading) == '-') iHeading++;

    heading = trim(substring(heading, iHeading));

    addPair(out, heading, lines(subList(lines, i1+1, i2)));

  }

  ret out;

}