Delegate method property to being triggered on conforming class - ios

Question

I have the following protocol
protocol SentenceDelegate: class{
func sentenceDidFinish()
}
I have my SentenceMarkov class conform to the protocol:
class SentenceMarkov : SentenceDelegate{
// foo
// bar
}
I implement the protocol method in my conforming class:
class SentenceMarkov : SentenceDelegate{
//...
func sentenceDidFinish{
//Do something
}
//...
}
I create a property on the class that calls the protocol method called sentenceDelegate :
class otherClass{
//..
weak var sentenceDelegate: SentenceDelegate?
//..
}
I set this property in my first class to self
class SentenceMarkov{
var FirstOne:OtherClass {
didSet { FirstOne.sentenceDelegate = self}
}
var SecondOne:OtherClass {
didSet{ SecondOne.sentenceDelegate = self}
}
init(Ult:OtherClass, Penult:OtherClass){
self.FirstOne= Ult
self.SecondOne = Penult
self.FirstOne.sentenceDelegate = self
self.SecondOne.sentenceDelegate = self
}
//..
}
Finally I call the sentenceDelegate method in OtherClass after its init()
class OtherClass{
func sentenceDone(){
sentenceDelegate?.sentenceDidFinish()
}
}
The problem is that, when I set breakpoints on the above method sentenceDelegate is nil. I am not sure why because I set it, although I could be setting it wrong, I am not sure how to ameliorate that though. Here is the three Swift files include the ViewController where SentenceMarkov is initialized:
https://gist.github.com/ebbnormal/e1cb791dd165a6866e11
https://gist.github.com/ebbnormal/263c9343e403c3a7ac40
https://gist.github.com/ebbnormal/1400e7da024d78ba5ed0

Answer 1

The following works for me:
protocol Greeter: class {
func greet()
}
class Dog {
weak var greeter: Greeter?
}
class DogPound: Greeter {
func greet() {
print("Hi. Welcome to the DogPound!")
}
var dog: Dog {
didSet {
dog.greeter = self
}
}
init(dog: Dog) {
self.dog = dog
self.dog.greeter = self
}
}
let myDog = Dog()
myDog.greeter?.greet() //=>nil
DogPound(dog: myDog)
myDog.greeter?.greet()
--output:--
Hi. Welcome to the DogPound!