public void add(AstBase n)
        {
            if (n instanceof AstSchemaHeader)
                {
                m_schemaHeader = (AstSchemaHeader) n;
                }
            else if (n instanceof AstDeclaration)
                {
                if (m_declaration == null)
                    {
                    m_declaration = (AstDeclaration) n;
                    }
                else
                    {
                    m_declaration.add(n);
                    }
                }
            else if (n instanceof AstPredicateList)
                {
                m_predicateList = (AstPredicateList) n;
                }
            else
                {
                super.add(n);
                }
        }