Created
April 4, 2023 12:43
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@dynamicMemberLookup | |
struct Identified<Value> { | |
let value: Value | |
let id: String | |
subscript<T>(dynamicMember keyPath: KeyPath<Value, T>) -> T { | |
value[keyPath: keyPath] | |
} | |
} | |
@dynamicMemberLookup | |
struct Timestamped<Value> { | |
let value: Value | |
let timestamp: Date | |
subscript<T>(dynamicMember keyPath: KeyPath<Value, T>) -> T { | |
value[keyPath: keyPath] | |
} | |
} | |
typealias Complete<T> = Timestamped<Identified<T>> | |
func complete(_ entry: Complete<User>) { | |
// ... | |
} | |
struct User { | |
let name: String | |
let age: UInt8 | |
} | |
let user = User(name: "Ian", age: 33) | |
let identified = Identified(value: user, id: UUID().uuidString) | |
let timestamped = Timestamped(value: identified, timestamp: .init()) | |
timestamped.timestamp // "Apr 4, 2023 at 8:42 AM" | |
timestamped.id // "66D63DA4-93E1-473A-8893-6A30767FFA8F" | |
timestamped.name // "Ian" | |
timestamped.age // 33 | |
complete(timestamped) // ✅ | |
complete(user) // ❌ | |
complete(identified) // ❌ |
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