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Functions and Closures *******

Example Type Function Write Function as closure Call function Call function using trailing closure syntax
() -> Void 

func sayHello() {
    print("Hello")
}

let sayHello: ()->Void = {print("Hello")}
Or 
let sayHello = {print("hello2")}
 sayHello() N/A?
(String) -> Void 

  func sayHello(name: String) {
      print("Hello \(name)")
  }

let sayHello: (String) -> Void = { name in print("Hello, \(name)")}
Or 
let sayHello = {(name:String) in print("Hello2, \(name)")}
 sayHello(name:"Nick") N/A?



Functions that use closures

*closures for parameters for functions
Example Type Function Write Function as closure Call function Call function using trailing closure syntax
(String, ()->Void) 

func sayHello(_ name:String, completion: ()->Void) {
    print("Hi, \(name)")
    completion()
}
write function as closure 

sayHello("nick", completion: {print("done.")})
  

sayHello("Nick")  {
  print("done)
}
(String, (String)->Void) 

func sayHello(_ name: String, completion: (String) -> Void) {
    print("Hello \(name) ")
    let reverseName = String(name.reversed())
    completion(reverseName)
}
write function as closure 

sayHello("Nick", completion:{ reverse_name in
    print(reverse_name)
    print("done.")
})
  

sayHello("Nick") { reverse_name in
    print(reverse_name)
}
Note: You can call a function or call a function using trailing closure syntax. The former could be called the "long way" or "formal way" but there is not name for it, that is just calling a function.