Merge pull request #19 from hegdeashwin/develop

Adds switch eg

Author: Ashwin Hegde

codes/ch3_branching/greet/greet.go

@@ -0,0 +1,95 @@
+package greet
+
+import "fmt"
+
+/**
+ * User defined type Profile act as struct type
+ */
+type Profile struct {
+	Name string
+	Username string
+	Message string
+}
+
+type Printer func(string) ()
+/**
+ * Define a CreateMessage function;
+ * 
+ * username is variadic function, can only use ... as final argument in list
+ */
+func CreateMessage(name, username, message string) (welcome string, info string) {
+
+	/**
+	 * <naming-return-val1> = string
+	 * <naming-return-val2> = string
+	 */
+	welcome = "\n" + message + " " + name
+	info = "You are authorize to access the system: " + username + "\n"
+
+	return
+}
+
+func Print(s string) {
+	fmt.Print(s)
+}
+
+func PrintLine(s string) {
+	fmt.Println(s)
+}
+
+func CreatePrintFunction(custom string) Printer {
+	return func(s string) {
+		fmt.Println(s + custom)
+	}
+}
+
+func GetPrefix(name string) (prefix string) {
+	/**
+	 * By default no break statement required.
+	 * Use fallthrought to continue with the following cases.
+	 * Cases can be expression.
+	 */
+	switch name {
+		case "Ashwin Hegde": 
+			prefix = "Mr. "
+			fallthrough
+
+		/**
+		 * Either `Issac Newton` or `Albert Einstein`.
+		 */
+		case "Isaac Newton", "Albert Einstein" : 
+			prefix = "Sir. "
+
+		default: 
+			prefix = "Dude. "
+	}
+
+	return
+}
+
+/**
+ * Define a Greet function;
+ */
+func Greet(github Profile, do Printer, isFormat bool) {
+	
+	wel, inf := CreateMessage(github.Name, github.Username, github.Message)
+
+	/**
+	 * Commenting exact below "Println(wel) line would throw an error "wel declared and not used"
+	 * In case you want to ignore the wel declaration and use info => replace wel with _ as below syntax
+	 *
+	 * E.g. _, info := CreateMessage(github.name, github.username, github.message)
+	 */
+
+	/**
+	 * if statement with embedded-statement
+	 * if [var] condition { ... } else { ... }
+	 */
+	if prefix := GetPrefix(github.Name); isFormat {
+		do(prefix + wel)
+	} else {
+		do(inf)	
+	}	
+
+	// fmt.Println(_)  // Cannot use _ as value
+}

codes/ch3_branching/switch.go

@@ -0,0 +1,13 @@
+package main
+
+import "./greet";
+
+func main() {
+
+	var github = greet.Profile{"Ashwin Hegde", "hegdeashwin", "Welcome to Go world!"}
+
+	/**
+	 * Call the function and pass the data to the function
+	 */
+	greet.Greet(github, greet.CreatePrintFunction("?"), true)
+}