asclass AbstractCompressor<A> extends Probabilistic {
  CompressionSearch<A> search;
  
  *() {}
  *(CompressionSearch<A> *search) {}
  
  void setSearch(CompressionSearch<A> search) {
    if (this.search != null && this.search != search) fail();
    this.search = search;
  }
  
  // get current best compressed representation
  abstract A currentBestDecompressor aka get();
}