Add region tags to the Go protobuf examples.

This will allow us to like to specific snippets of code in the
documentation.  I plan to create a tutorial similar to the C# tutorial
https://developers.google.com/protocol-buffers/docs/csharptutorial

Since that tutorial has sections for populating a proto, parsing, and
serializing, I made a region for each of these for Go.  To make the
populating sample more self-contained, I refactor the listing example
slightly.

1 files changed, 24 insertions, 22 deletions

diff --git a/examples/list_people.go b/examples/list_people.go
index 48b1fbfa..70bc589e 100644
--- a/examples/list_people.go
+++ b/examples/list_people.go
@@ -11,25 +11,29 @@ import (
 	pb "github.com/google/protobuf/examples/tutorial"
 )
 
-func listPeople(w io.Writer, book *pb.AddressBook) {
-	for _, p := range book.People {
-		fmt.Fprintln(w, "Person ID:", p.Id)
-		fmt.Fprintln(w, "  Name:", p.Name)
-		if p.Email != "" {
-			fmt.Fprintln(w, "  E-mail address:", p.Email)
-		}
+func writePerson(w io.Writer, p *pb.Person) {
+	fmt.Fprintln(w, "Person ID:", p.Id)
+	fmt.Fprintln(w, "  Name:", p.Name)
+	if p.Email != "" {
+		fmt.Fprintln(w, "  E-mail address:", p.Email)
+	}
 
-		for _, pn := range p.Phones {
-			switch pn.Type {
-			case pb.Person_MOBILE:
-				fmt.Fprint(w, "  Mobile phone #: ")
-			case pb.Person_HOME:
-				fmt.Fprint(w, "  Home phone #: ")
-			case pb.Person_WORK:
-				fmt.Fprint(w, "  Work phone #: ")
-			}
-			fmt.Fprintln(w, pn.Number)
+	for _, pn := range p.Phones {
+		switch pn.Type {
+		case pb.Person_MOBILE:
+			fmt.Fprint(w, "  Mobile phone #: ")
+		case pb.Person_HOME:
+			fmt.Fprint(w, "  Home phone #: ")
+		case pb.Person_WORK:
+			fmt.Fprint(w, "  Work phone #: ")
 		}
+		fmt.Fprintln(w, pn.Number)
+	}
+}
+
+func listPeople(w io.Writer, book *pb.AddressBook) {
+	for _, p := range book.People {
+		writePerson(w, p)
 	}
 }
 
@@ -41,19 +45,17 @@ func main() {
 	}
 	fname := os.Args[1]
 
+	// [START unmarshal_proto]
 	// Read the existing address book.
 	in, err := ioutil.ReadFile(fname)
 	if err != nil {
-		if os.IsNotExist(err) {
-			fmt.Printf("%s: File not found.  Creating new file.\n", fname)
-		} else {
-			log.Fatalln("Error reading file:", err)
-		}
+		log.Fatalln("Error reading file:", err)
 	}
 	book := &pb.AddressBook{}
 	if err := proto.Unmarshal(in, book); err != nil {
 		log.Fatalln("Failed to parse address book:", err)
 	}
+	// [END unmarshal_proto]
 
 	listPeople(os.Stdout, book)
 }