sclass ParsedWithTokens<A> extends Var<A> {
  LS tok; // full CNC token list being parsed
  int iStart; // points to first parsed C token
  int iRemaining; // points to first unparsed C token
  
  *() {}
  *(A a) { super(a); }
  *(A a, LS *tok, int *iStart, int *iRemaining) { super(a); }
  
  ListAndIndex<S> remaining() { ret ListAndIndex(tok, iRemaining); }
  
  <B> ParsedWithTokens<B> withValue(B b) {
    ret new ParsedWithTokens<B>(b, tok, iStart, iRemaining);
  }
}