sclass ActualThoughtSpace extends AbstractThoughtSpace implements AI_PostHandler, AI_CacheChecker {
  new TripleIndex index;
  int limit; // 0 = no limit

  *() {}
  *(int *limit) {}
  
  // existence of triple has already been checked
  public S postTriple(T3<S> t) {
    if (limitReached()) fail("Thought space limit reached");
    TripleWeb w = tripleWeb(t);
    index.addTriple(w);
    ret w.globalID();
  }
  
  bool limitReached() {
    ret limit > 0 && size() >= limit;
  }
  
  L<WebNode> get(S s) {
    ret index.get(ai_shortenForIndex(s));
  }
  
  int size() { ret l(websByID); }
}