fix: coding style and file format for chapter 11, 12, 13, 14 and 15.

eBook/exercises/chapter_11/interface_nil.go

@@ -1,46 +1,46 @@
-// interface_nil.go
-package main
-
-import "fmt"
-
-type Any interface {}
-type Anything struct {}
-
-func main() {
-	any := getAny()
-	if any == nil {
-		fmt.Println("any is nil")
-	} else {
-		fmt.Println("any is not nil")
-	}
-/*
-	// to get the inner value:
-	anything := any.(*Anything) 
-	if anything == nil {
-		fmt.Println("anything is nil")
-	} else {
-		fmt.Println("anything is not nil")
-	}
-*/
-}
-
-func getAny() Any {
-	return getAnything()
-}
-
-func getAnything() *Anything {
-	return nil
-}
-
-/* Output:
-any is not nil
-WHY?
-you would perhaps expect: any is nil,because getAnything() returns that
-BUT:
-the interface value any is storing a value, so it is not nil. 
-It just so happens that the particular value it is storing is a nil pointer.
-The any variable has a type, so it's not a nil interface, 
-rather an interface variable with type Any and concrete value (*Anything)(nil).
-To get the inner value of any, use: anything := any.(*Anything)
-now anything contains nil !
-*/
+// interface_nil.go
+package main
+
+import "fmt"
+
+type Any interface{}
+type Anything struct{}
+
+func main() {
+	any := getAny()
+	if any == nil {
+		fmt.Println("any is nil")
+	} else {
+		fmt.Println("any is not nil")
+	}
+	/*
+		// to get the inner value:
+		anything := any.(*Anything)
+		if anything == nil {
+			fmt.Println("anything is nil")
+		} else {
+			fmt.Println("anything is not nil")
+		}
+	*/
+}
+
+func getAny() Any {
+	return getAnything()
+}
+
+func getAnything() *Anything {
+	return nil
+}
+
+/* Output:
+any is not nil
+WHY?
+you would perhaps expect: any is nil,because getAnything() returns that
+BUT:
+the interface value any is storing a value, so it is not nil.
+It just so happens that the particular value it is storing is a nil pointer.
+The any variable has a type, so it's not a nil interface,
+rather an interface variable with type Any and concrete value (*Anything)(nil).
+To get the inner value of any, use: anything := any.(*Anything)
+now anything contains nil !
+*/