[英]Swift: How to check for generic type in a reflection?
我有以下型号:
class BaseClass { ... }
class WeakCollection<T: BaseClass> { ... }
class Person : BaseClass { ... }
class Parent : Person {
var children: [Child]
...
}
class Child : Person {
var parents: WeakCollection<Parent>
...
}
let aChild = Child()
...
我正在使用这样的反射:
let mirrored_object = Mirror(reflecting: aChild)
for attr in mirrored_object.children {
switch attr.value {
case is Int:
...
case is String:
...
case is WeakCollection<BaseClass>:
...
}
}
问题是在case is WeakCollection<BaseClass>
的检查总是假如果泛型类型不是直接BaseClass
本身,也就是说,如果它是它的一些子类,则此检查将是假的。 如何检查泛型类型?
一个粗略的方法是让你的“WeakCollection”从某种协议继承:
protocol BaseProtocol {}
class WeakCollection<T> : BaseProtocol
然后在您的交换机中这样做:
switch attr.value {
case is String:
// This is a string
break
case let optionalObject as Optional<Any>:
if case .some(let complexObject) = optionalObject
{
if (complexObject is BaseProtocol)
{
// This is a "WeakCollection" kind
}
}
break
}
这有点粗糙,但它给出了你想要的输出。
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