public override IList <IModelItem> getChildren()
        {
            List <IModelItem> list = new List <IModelItem>();

            list.Add(LexemFactory.getInstance().getLexem(LEFT_BRACKET));
            list.Add(_constant);
            if (!_terms.isEmpty())
            {
                list.Add(DELIMITER);
                list.AddRange(_terms.getChildren());
            }
            if (_variable != null)
            {
                list.Add(DELIMITER);
                list.Add(_variable);
            }
            list.Add(LexemFactory.getInstance().getLexem(RIGHT_BRACKET));
            return(list);
        }
        public override IList <IModelItem> getChildren()
        {
            List <IModelItem> result       = new List <IModelItem>();
            LexemFactory      lexemFactory = LexemFactory.getInstance();

            result.Add(lexemFactory.getLexem(LEFT_BRACKET));
            result.Add(new KifConstant(getConstant()));
            if (!(_termSeq == null || _termSeq.isEmpty()))
            {
                result.Add(DELIMITER);
                result.AddRange(_termSeq.getChildren());
            }
            if (_sequenceVar != null)
            {
                result.Add(DELIMITER);
                result.Add(_sequenceVar);
            }
            result.Add(lexemFactory.getLexem(RIGHT_BRACKET));
            return(result);
        }