// A = type of literals (e.g. String)
static noeq record LineCompedSingle<A>(L<A> literals, L<IntPair> pairs, L<Int> main) {
  long roughCount() { ret l(literals) + l(pairs)*2 + l(main); }
  int nLiterals() { ret l(literals); }
  int nItems() { ret l(literals) + l(pairs); }
  
  IntPair getPair(int symbol) { ret pairs.get(symbol-l(literals)); }
}