Add monostate example

Author: Tavernari

Design-Patterns.playground.zip

@@ -192,6 +192,43 @@ CurrencyFactory.currency(for: .greece)?.code ?? noCurrencyCode
 CurrencyFactory.currency(for: .spain)?.code ?? noCurrencyCode
 CurrencyFactory.currency(for: .unitedStates)?.code ?? noCurrencyCode
 CurrencyFactory.currency(for: .uk)?.code ?? noCurrencyCode
+/*:
+ 🔂 Monostate
+ ------------
+
+ The monostate pattern is a alternativa to singleton, so in that case monostate still
+ the state as static instead of all object as singleton. You can use a protocol to apply
+ dependency inversion helping you on unit tests.
+
+### Example:
+*/
+struct Settings {
+
+    enum Theme {
+        case .old
+        case .new
+    }
+
+    private static var theme: Theme
+
+    var currentTheme: Theme {
+        get { Settings.theme }
+        set(newTheme) { Settings.theme = newTheme }
+    }
+}
+/*:
+### Usage:
+*/
+
+// When change the theme
+let settings = Settings() // Starts using theme .old
+settings.theme = .new // Change theme to .new
+
+//On Screen 1
+let screenColor: Color = Settings().theme == .old ? .gray : .white
+
+//On Screen 2
+let screenTitle: String = Settings().theme == .old ? "Itunes Connect" : "App Store Connect"
 /*:
 🃏 Prototype
 ------------

Design-Patterns.playground/Pages/Creational.xcplaygroundpage/Contents.swift

@@ -1002,6 +1002,47 @@ CurrencyFactory.currency(for: .greece)?.code ?? noCurrencyCode
 CurrencyFactory.currency(for: .spain)?.code ?? noCurrencyCode
 CurrencyFactory.currency(for: .unitedStates)?.code ?? noCurrencyCode
 CurrencyFactory.currency(for: .uk)?.code ?? noCurrencyCode
+```
+
+ 🔂 Monostate
+ ------------
+
+ The monostate pattern is a alternativa to singleton, so in that case monostate still
+ the state as static instead of all object as singleton. You can use a protocol to apply
+ dependency inversion helping you on unit tests.
+
+### Example:
+
+```swift
+struct Settings {
+
+    enum Theme {
+        case .old
+        case .new
+    }
+
+    private static var theme: Theme
+
+    var currentTheme: Theme {
+        get { Settings.theme }
+        set(newTheme) { Settings.theme = newTheme }
+    }
+}
+```
+
+### Usage:
+
+```swift
+
+// When change the theme
+let settings = Settings() // Starts using theme .old
+settings.theme = .new // Change theme to .new
+
+//On Screen 1
+let screenColor: Color = Settings().theme == .old ? .gray : .white
+
+//On Screen 2
+let screenTitle: String = Settings().theme == .old ? "Itunes Connect" : "App Store Connect"
 ```
 
 🃏 Prototype

README.md

@@ -0,0 +1,37 @@
+/*:
+ 🔂 Monostate
+ ------------
+
+ The monostate pattern is a alternativa to singleton, so in that case monostate still
+ the state as static instead of all object as singleton. You can use a protocol to apply
+ dependency inversion helping you on unit tests.
+
+### Example:
+*/
+struct Settings {
+
+    enum Theme {
+        case .old
+        case .new
+    }
+
+    private static var theme: Theme
+
+    var currentTheme: Theme {
+        get { Settings.theme }
+        set(newTheme) { Settings.theme = newTheme }
+    }
+}
+/*:
+### Usage:
+*/
+
+// When change the theme
+let settings = Settings() // Starts using theme .old
+settings.theme = .new // Change theme to .new
+
+//On Screen 1
+let screenColor: Color = Settings().theme == .old ? .gray : .white
+
+//On Screen 2
+let screenTitle: String = Settings().theme == .old ? "Itunes Connect" : "App Store Connect"