gistfile1.swift

extension AttributeContainer {
   init<S: AttributeScope>(_ keyPath: KeyPath<AttributeScopes, S.Type>, builder: (inout ScopedAttributeContainer<S>) -> Void) {
       self.init()
       builder(&self[dynamicMember: keyPath])
   }

   static subscript<S>(dynamicMember keyPath: KeyPath<AttributeScopes, S.Type>) -> ((inout ScopedAttributeContainer<S>) -> Void) -> AttributeContainer where S: AttributeScope {
       { AttributeContainer(keyPath, builder: $0) }
   }
}

let titleAttr = AttributeContainer(\.uiKit) {
    $0.foregroundColor = .black
}

let titleAttr = AttributeContainer.uiKit {
    $0.foregroundColor = .black
}