Property

@propertyWrapper
public struct Property<T>

A property wrapper which allows ClassHook types to add new properties to their hooked class.

This type is an ergonomic wrapper around Objective-C associated objects. The type of the associated object is the generic argument T.

If you are declaring a property on a ClassHook, you likely want to use this. Note that this property only works on types which conform to ClassHook.

Attributes

This property wrapper gives you the ability to specify attributes on the property, which are similar to those used by Objective-C’s @property. For a description of each attribute, see Property.Assign, Property.Atomicity, and Property.RetainOrCopy.

The default attributes are atomic and retain. Specifying assign will replace both defaults, and specifying an atomicity and/or retain policy will only override the respective default.

Example

@objcMembers class Person: NSObject {
    dynamic func sayHello() -> String {
        "hello"
    }
}

class PersonHook: ClassHook<Person> {
    @Property(.nonatomic) var x = 0

    func sayHello() -> String {
        x += 1
        return "Hi! I've been called \(x) time(s)"
    }
}

// later...

let alice = Person()
alice.sayHello() // Hi! I've been called 1 time(s)
alice.sayHello() // Hi! I've been called 2 time(s)

let bob = Person()
bob.sayHello() // Hi! I've been called 1 time(s)
bob.sayHello() // Hi! I've been called 2 time(s)