MathMLElement* elem = (node != NULL) ? (MathMLElement*) (mdom_node_get_user_data(node)) : NULL;
MathMLElement* elem = (node != NULL) ? findMathMLElement(node) : NULL;
gtk_math_view_set_selection(GtkMathView* math_view, mDOMNodeRef node){  g_return_if_fail(math_view != NULL);  g_return_if_fail(math_view->interface != NULL);  // WARNING: the following is a very dangerous operation. It relies  // of the assumption that the user will NEVER modify the user data field  // in the DOM tree elements!!!  MathMLElement* elem = (node != NULL) ? (MathMLElement*) (mdom_node_get_user_data(node)) : NULL;  math_view->interface->SetSelected(elem);}