added visitor and facade

Author: Sebastian Boldt

Behavioral.playground/Pages/Untitled Page.xcplaygroundpage/Contents.swift

@@ -0,0 +1,49 @@
+//: [Previous](@previous)
+
+import Foundation
+
+protocol Country {
+    func accept(visitor: Visitor)
+}
+
+protocol Visitor {
+    var age: Int { get }
+    func visit(country: Country)
+}
+
+class Germany: Country {
+    func accept(visitor: Visitor) {
+        if visitor.age >= 18 {
+            visitor.visit(country: self)
+        }
+    }
+}
+
+class USA: Country {
+    func accept(visitor: Visitor) {
+        if visitor.age >= 18 {
+            visitor.visit(country: self)
+        }
+    }
+}
+
+class Peter: Visitor {
+    var age: Int
+    
+    init(age: Int) {
+        self.age = age
+    }
+    var visitedCountries: [Country] = []
+    func visit(country: Country) {
+        visitedCountries.append(country)
+    }
+}
+
+let usa = USA()
+let germany = Germany()
+
+let peter = Peter(age: 19)
+
+germany.accept(visitor: peter)
+
+print(peter.visitedCountries.last!)

Behavioral.playground/Pages/Untitled Page.xcplaygroundpage/timeline.xctimeline

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Timeline
+   version = "3.0">
+   <TimelineItems>
+   </TimelineItems>
+</Timeline>

GOFSwift.xcworkspace/xcuserdata/sebastianboldt.xcuserdatad/UserInterfaceState.xcuserstate

@@ -12,11 +12,11 @@
 * ✅ Iterator
 * ✅ Strategy
 * ✅ Mediator
+* ✅ Visitor
 * ❌ Interpreter
 * ❌ Memento
 * ❌ Observer
 * ❌ State
-* ❌ Visitor
 
 ##Creational
 
@@ -33,7 +33,7 @@
 * ✅ Decorator
 * ✅ Composite
 * ✅ Adapter
-* ❌ Facade
+* ✅ Facade
 * ❌ Flyweight
 * ❌ Protection Proxy
 * ❌ Virtual Proxy

README.md

@@ -0,0 +1,23 @@
+//: [Previous](@previous)
+
+import Foundation
+
+//The facade pattern is used to define a simplified interface to a more complex subsystem.
+
+enum Eternal {
+    
+    static func set(_ object: Any, forKey defaultName: String) {
+        let defaults: UserDefaults = UserDefaults.standard
+        defaults.set(object, forKey:defaultName)
+        defaults.synchronize()
+    }
+    
+    static func object(forKey key: String) -> AnyObject! {
+        let defaults: UserDefaults = UserDefaults.standard
+        return defaults.object(forKey: key) as AnyObject!
+    }
+    
+}
+
+Eternal.set("Disconnect me. I’d rather be nothing", forKey:"Bishop")
+Eternal.object(forKey: "Bishop")

Structural.playground/Pages/Facade.xcplaygroundpage/Contents.swift

@@ -5,5 +5,6 @@
         <page name='Decorator'/>
         <page name='Composite'/>
         <page name='Adapter'/>
+        <page name='Facade'/>
     </pages>
 </playground>