update book code

eBook/examples/chapter_10/embed_func1.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"fmt"
+)
+
+type Log struct {
+	msg string
+}
+
+type Customer struct {
+    Name	string
+    log 	*Log
+}
+
+func main() {
+	// c := new(Customer)
+	// c.Name = "Barak Obama"
+	// c.log = new(Log)
+	// c.log.msg = "1 - Yes we can!"
+	// shorter:
+	c := &Customer{"Barak Obama", &Log{"1 - Yes we can!"}}
+	// fmt.Println(c)   // &{Barak Obama 1 - Yes we can!}
+	c.Log().Add("2 - After me the world will be a better place!")
+	//fmt.Println(c.log)
+	fmt.Println(c.Log())
+}
+
+func (l *Log) Add(s string) {
+	l.msg += "\n" + s
+}
+
+func (l *Log) String() string {
+	return l.msg
+}
+
+func (c *Customer) Log() *Log {
+    return c.log
+}
+/* Output:
+1 - Yes we can!
+2 - After me the world will be a better place!
+*/