anchor.diff:  
   q = query;
   
  +//TODO other stuff
   };
   
   //
  
positive.code:   
  //
  operation :
   equalityop | locationop | containsop;
  
  //negations of operations
  notexp :
  
negative.code: 
  //root level boolean expression
  expression:
    orexp;
  
  //direction for ordering
  direction  : ('asc' | 'desc');
  
  //order cause
  order
    : (property direction?);
  
  