如何简化 Swift 数组初始化

Question

这是对 https://stackoverflow.com/a/47765972/8833459 的引用。 给出以下声明：

let fooPaths: [WritableKeyPathApplicator<Foo>] = [WritableKeyPathApplicator(Foo.bar), WritableKeyPathApplicator(Foo.baz)]

是否有一个 init 或其他可以做的事情，以便以下(或类似的东西(也可以工作？

let fooPaths: [WritableKeyPathApplicator<Foo>] = [Foo.bar, Foo.baz]

原话实在是打字太多了！ 我的"首选"方法当前给出错误：

error: cannot convert value of type 'WritableKeyPath<Foo, String>' to expected element type 'WritableKeyPathApplicator<Foo>'

Answer 1

类型是不必要的：

let fooPaths = [WritableKeyPathApplicator(Foo.bar), WritableKeyPathApplicator(Foo.baz)]

第二Foo是不必要的。

let fooPaths = [WritableKeyPathApplicator(Foo.bar), WritableKeyPathApplicator(.baz)]

如果您确实提供了类型，则也是第一个：

let fooPaths: [WritableKeyPathApplicator<Foo>] = [WritableKeyPathApplicator(.bar),
WritableKeyPathApplicator(.baz)]

如果主要关注点是键入，请添加本地类型别名：

typealias WKPA<T> = WritableKeyPathApplicator<T>
let fooPaths: [WKPA<Foo>] = [WKPA(.bar),
WKPA(.baz)]