Swift 3 ObjectOriented Programming - Second Edition

Working with function types within classes

The following lines declare a myFunction variable with a function type, specifically, a function that receives an Int argument and returns a Bool value. The variable works in the same way as an argument that specifies a function type for a function. The code file for the sample is included in the swift_3_oop_chapter_07_05 folder:

    var myFunction: ((Int) -> Bool) 
    myFunction = divisibleBy5 
    let myNumber = 20 
    print("Is \(myNumber) divisible by 5: \(myFunction(myNumber))") 

Then, the code assigns the divisibleBy5 function to myFunction. It is very important to understand that the line doesn't call the divisibleBy5 function and save the result of this call in the myFunction variable. Instead, it just assigns ...