!7

sclass LinkedToken {
  S t;
  LinkedToken prev, next;
  LinkedToken prevIdentical, nextIdentical;
  
  *() {}
  *(S *t) {}
}

sclass Tokenization {
  LinkedToken first, last;
  new Map<S, LinkedToken> firstByContent;
  new Map<S, LinkedToken> lastByContent;
}

p {
  L<S> tokens = javaTok(text);
  
  new Tokenization tok;
  for i over tokens: {
    S t = tok.get(i);
    LinkedToken lt = new(t);
    lt.t = t;
    if (tok.first == null)
      tok.first = lt;
    else {
      lt.prev = tok.last;
      tok.last.next = lt;
    }
    tok.last = lt;
    LinkedToken prevIdentical = tok.lastByContent.get(t);
    if (prevIdentical == null)
      tok.firstByContent.put(t, lt);
  }
  
  tok = LinkedList<LinkedToken>
}