/// <summary>
        /// Добавить присваивание
        /// </summary>
        /// <param name="formula">Узел, содкржащий формулу</param>
        protected void InsertAssignment(XmlNode formula)
        {
            try
            {
                Formula    frm        = new Formula();
                Assignment assignment = new Assignment();

                frm.Position = GetPosition(formula);
                XmlNode macros = GetMacros(formula);

                if (macros != null)
                {
                    assignment.InstanceMacrosFromXmlNode(macros);

                    frm.Macros = assignment;
                    InsertFormula(frm);
                }
            }
            catch
            {
            }
        }
        /// <summary>
        /// Добавить присваивание
        /// </summary>
        /// <param name="formula">Узел, содкржащий формулу</param>
        protected void InsertAssignment(XmlNode formula)
        {
            try
            {
                Formula frm = new Formula();
                Assignment assignment = new Assignment();

                frm.Position = GetPosition(formula);
                XmlNode macros = GetMacros(formula);

                if (macros != null)
                {
                    assignment.InstanceMacrosFromXmlNode(macros);

                    frm.Macros = assignment;
                    InsertFormula(frm);
                }
            }
            catch
            {
            }
        }