Initial commit - learning the basics

hello/go.mod

@@ -0,0 +1,7 @@
+module learning.local/hello
+
+go 1.24.5
+
+replace learning.local/using_modules => ../using_modules
+
+require learning.local/using_modules v0.0.0-00010101000000-000000000000

hello/hello.go

@@ -0,0 +1,28 @@
+package main
+
+import ( 
+	"fmt"
+	"log"
+	
+	"learning.local/using_modules"
+)
+
+func main () {
+	// Set properties of the predefined Logger, including
+	// the log entry prefix and a flag to disable printing
+	// the time, source fiile, and line number.
+	log.SetPrefix("using_modules: ")
+	log.SetFlags(0)
+	
+	// A slice of names
+	names := []string{"Gladys", "Yoda", "Darth Vader"}
+	
+	// Request greeting messages for the names
+	messages, err := using_modules.Hellos(names)
+	if err != nil {
+		log.Fatal(err)
+	}
+	// If no error was returned, print the returned map of
+	// messages to the console
+	fmt.Println(messages)
+}

hello/using_modules.go

@@ -0,0 +1,35 @@
+package using_modules
+
+import (
+	"fmt"
+	"errors"
+	"math/rand"
+)
+
+// Hello returns a greeting for the named person
+func Hello(name string) (string, error) {
+	// If no name was given, return an error with a message
+	if name == "" {
+		return "", errors.New("Empty name!")
+	}
+
+	message := fmt.Sprintf(randomFormat(), name)
+	return message, nil
+}
+
+
+// randomFormat returns one of a set of greeting messages. The returned
+// message is selected at random.
+
+func randomFormat() string {
+	// A slice of message formats
+	formats := []string{
+		"Hi, %v. Welcome!",
+		"Great to see you, %v",
+		"Hail, %v! Well met!",
+	}
+
+	// Return a randomly selected message format by specifying
+	// a random index for the slice of formats.
+	return formats[rand.Intn(len(formats))]
+}