interfaces: refactor

interfaces/01-methods/book.go

@@ -0,0 +1,36 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+type book struct {
+	title string
+	price float64
+}
+
+func (b book) print() {
+	// b is a copy of the original `book` value here.
+	fmt.Printf("%-15s: $%.2f \n", b.title, b.price)
+}
+
+// ----------------------------------------------------------------------------
+// + you can use the same method names among different types.
+// + you don't need to type `printGame`, it's just: `print`.
+//
+// func (b book) printBook() {
+// 	// b is a copy of the original `book` value here.
+// 	fmt.Printf("%-15s: $%.2f \n", b.title, b.price)
+// }
+
+// ----------------------------------------------------------------------------
+// b is a copy of the original `book` value here.
+//
+// func printBook(b book) {
+// 	fmt.Printf("%-15s: $%.2f \n", b.title, b.price)
+// }

interfaces/01-methods/game.go

@@ -0,0 +1,36 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+type game struct {
+	title string
+	price float64
+}
+
+func (g game) print() {
+	fmt.Printf("%-15s: $%.2f\n", g.title, g.price)
+}
+
+// PREVIOUS CODE:
+
+// ----------------------------------------------------------------------------
+// you can use same method name among different types.
+// you don't need to type `printGame`, it's just: `print`.
+//
+// func (g game) printGame() {
+// 	fmt.Printf("%-15s: $%.2f\n", g.title, g.price)
+// }
+
+// ----------------------------------------------------------------------------
+// you cannot use the same function name within the same package.
+//
+// func printGame(g game) {
+// 	fmt.Printf("%-15s: $%.2f\n", g.title, g.price)
+// }

interfaces/01-methods/main.go

@@ -0,0 +1,46 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	mobydick := book{
+		title: "moby dick",
+		price: 10,
+	}
+
+	minecraft := game{
+		title: "minecraft",
+		price: 20,
+	}
+
+	tetris := game{
+		title: "tetris",
+		price: 5,
+	}
+
+	// #4: method expressions
+	// methods are just functions that receive a value of a type.
+	game.print(minecraft) // sends `minecraft` value to `game.print`
+	game.print(tetris)    // sends `tetris` value to `game.print`
+	fmt.Println()
+
+	// #3
+	mobydick.print()  // sends `mobydick` value to `book.print`
+	minecraft.print() // sends `minecraft` value to `game.print`
+	tetris.print()    // sends `tetris` value to `game.print`
+
+	// #2
+	// mobydick.printBook()
+	// minecraft.printGame()
+
+	// #1
+	// printBook(mobydick)
+	// printGame(minecraft)
+}