static LineCompedSingle<Char> lineCompedSingleFromCompressor(LineCompCompressor compressor) {
  new L<Char> literals;
  new L<IntPair> pairs;
  for (LineCompCompressor.Chunk c : compressor.chunks)
    if (c cast LineCompCompressor.CPair)
      pairs.add(IntPair(c.i1, c.i2));
    else
      literals.add(charFromHex(((LineCompCompressor.CPrim) c).s));
  ret new LineCompedSingle<Char>(literals, pairs, firstValue(compressor.finalEncodings));
}

Began life as a copy of #1028766