code: private Collection<Tuple> getUncombinedTuples( List<VarDef> uncombinedVars, int defaultTupleSize)
      {
      Collection<Tuple> tuples = TupleCombiner.getTuples( uncombinedVars, defaultTupleSize);
      if( defaultTupleSize == 1)
        {
        for( Tuple tuple : tuples)
          {
          VarValueDef value = tuple.getBindings().next().getValueDef();
          tuple.setOnce( value.getType() == VarValueDef.Type.ONCE);
          }
        }
      return tuples;
      }
docs: Returns default tuples for all uncombined variables.