Tidy up tutorials

tutorials/basics/main.go

@@ -13,6 +13,17 @@ type model struct {
 	selected map[int]struct{}
 }
 
+func initialModel() model {
+	return model{
+		choices: []string{"Buy carrots", "Buy celery", "Buy kohlrabi"},
+
+		// A map which indicates which choices are selected. We're using
+		// the  map like a mathematical set. The keys refer to the indexes
+		// of the `choices` slice, above.
+		selected: make(map[int]struct{}),
+	}
+}
+
 func (m model) Init() tea.Cmd {
 	return nil
 }
@@ -67,12 +78,7 @@ func (m model) View() string {
 }
 
 func main() {
-	initialModel := model{
-		choices:  []string{"Carrots", "Celery", "Kohlrabi"},
-		selected: make(map[int]struct{}),
-	}
-
-	p := tea.NewProgram(initialModel)
+	p := tea.NewProgram(initialModel())
 	if err := p.Start(); err != nil {
 		fmt.Printf("Alas, there's been an error: %v", err)
 		os.Exit(1)