Simple pop operation to simplify a common setup

01_pop.swift

func pop<T>(
  _ maybeValue: inout T?,
  _ block: ((T) -> Void)
) {
  guard let value = maybeValue else { return }
  maybeValue = nil
  block(value)
}

02_example-before.swift

class Example {
  var someStoredThing : String?
  
  func cleanup() {
    if let thing = self.someStoredThing {
      print("Got a thing: \(thing)")
      self.someStoredThing = nil
    }
  }
}

03_example-after.swift

class Example {
  var someStoredThing : String?
  
  func cleanup() {
    pop(&self.someStoredThing) { thing in
      print("Got a thing: \(thing)")
    }
  }
}