有没有办法让三元运算符适用于Cloud Firestore安全规则？

service cloud.firestore {
  match /databases/{database}/documents {
    function isDocumentPublic() {
      return request.auth != null && request.auth.uid == resource.data.owner;
    }

    match /collection/{document} {
      allow read: if isDocumentPublic() || request.auth.uid == 'admin';
      allow write: if isDocumentPublic() ? false : request.auth.uid == 'admin';
    }
  }
}