sclass C {
  char c;
  bool output;
 
  *() {}
  *(char *c, bool *output) {}
  
  public bool equals(O o) {
    ret o instanceof C && c == ((C) o).c && output == ((C) o).output;
  }
  
  public int hashCode() {
    ret (int) c + (output ? 0x1000 : 0);
  }
}

static L<C> poemToC(S poemID) {
  new L<C> l;
  for (E e : parsePoem(poemID))
    if (e.q != null)
      addC(l, e.q + "\n", false);
    else if (e.a != null)
      addC(l, e.a + "\n", true);
  ret l;
}

static void addC(L<C> script, S s, bool output) {
  for (char c : asChars(s))
    script.add(new C(c, output));
}

static L<E> poemFromC(L<C> script) {
  new L<E> l;
  int i = 0;
  while (i < l(script)) {
    new E e;
    int j = poemFromC_scan(script, i, false);
    if (j > i)
      e.q = poemFromC_join(script, i, j);
    else {
      j = poemFromC_scan(script, i, true);
      assertTrue(j > i);
      e.a = poemFromC_join(script, i, j);
    }
    l.add(e);
    i = j;
  }
  ret l;
}

static int poemFromC_scan(L<C> script, int i, bool output) {
  while (i < l(script) && script.get(i).output == output)
    ++i;
  ret i;
}

static S poemFromC_join(L<C> script, int i, int j) {
  new StringBuilder buf;
  for (; i < j; i++)
    buf.append(script.get(i).c);
  ret str(buf);
}