Place the following code in an XCode Play Ground:
import UIKit
struct Person {
let birthYear : Int
let name : String
let tag : String
}
//The build function allows a builder function to be passed in. That function
//can create a new person based on the paramaters passed in
extension Person {
static func build(birthYear: Int, name: String, tag: String, builder: (_ birthYear: Int, _ name : String, _ tag: String) -> Person) -> Person {
return builder(birthYear, name, tag)
}
}
//Functions can have argument labels and parameter names
//Argument labels and Parameter names
func personBuilderOne(theBirthYear birthYear: Int, theName name: String, theTag tag: String) -> Person {
return Person(birthYear: birthYear, name: name, tag: tag + " Builder One")
}
//No Argument labels, just parameter names
func personBuilderTwo(birthYear: Int, name: String, tag: String) -> Person {
return Person(birthYear: birthYear, name: name, tag: tag + " Builder Two")
}
//Parameter names are not needed when calling
func personBuilderThree(_ birthYear: Int, _ name: String, _ tag: String) -> Person {
return Person(birthYear: birthYear, name: name, tag: tag + " Builder Three")
}
//----------------------------------------------------------
//Notice how the signature changes for the function paramter
var person = Person.build(birthYear: 1900, name: "John", tag: "tag", builder: personBuilderOne(theBirthYear:theName:theTag:))
print(person)
person = Person.build(birthYear: 1900, name: "John", tag: "tag", builder: personBuilderTwo(birthYear:name:tag:))
print(person)
person = Person.build(birthYear: 1900, name: "John", tag: "tag", builder: personBuilderThree(_:_:_:))
print(person)
//----------------------------------------------------------
//The builder can be done by using a closure
//The closure params are contrived just to show how they are used
person = Person.build(birthYear: 1910, name: "Mary", tag: "tag") { bYear, theName, theTag in
return Person(birthYear: bYear, name: theName, tag: theTag + " Closure")
}
print(person)
Person(birthYear: 1900, name: "John", tag: "tag Builder One")
Person(birthYear: 1900, name: "John", tag: "tag Builder Two")
Person(birthYear: 1900, name: "John", tag: "tag Builder Three")
Person(birthYear: 1910, name: "Mary", tag: "tag Closure")
