anchor.diff:    
     Opt_labels = fetch_option(labels, Dict, binary),
     Opt_float = fetch_option(float, Dict, true),
  -  Opt_duplicate_labels = fetch_option(duplicate_labels, Dict, true),
     
     #options{
       labels = Opt_labels,
       float = Opt_float,
  -    duplicate_labels = Opt_duplicate_labels,
   
       binary_to_label   = binary_to_label_fun(Opt_labels),
  -
       tuple_to_number = tuple_to_number_fun(Opt_float)
     }.
   
  
positive.code:   % original values
    labels,
    float,
    duplicate_labels,
  
    % implementations
    binary_to_label, tuple_to_number
  
negative.code: 
  binary_to_label_fun(binary)         -> fun identity/1; 
  binary_to_label_fun(atom)           -> fun to_atom/1;
  binary_to_label_fun(existing_atom)  -> fun to_existing_atom/1;
  binary_to_label_fun(X) -> io:format("Unsupported labels value ~p ~n", [ X ]). 
  
  %% Convert numbers
  
  