void swap_guid(const ValueNode::Handle& a,const ValueNode::Handle& b) { synfig::GUID old_a(a->get_guid()); a->set_guid(synfig::GUID()); synfig::GUID old_b(b->get_guid()); b->set_guid(synfig::GUID()); a->set_guid(old_b); b->set_guid(old_a); }