Add CommandRouter.SubGroup

router.go

@@ -64,6 +64,13 @@ func (c *CommandRouter) SubFunc(pattern string, cmd CommandFunc) {
 	c.Sub(pattern, cmd)
 }
 
+// SubGroup is a convenience method for adding a subcommand with a new router.
+func (c *CommandRouter) SubGroup(pattern string, cb func(r *CommandRouter)) {
+	r := NewCommandRouter()
+	cb(r)
+	c.Sub(pattern, r)
+}
+
 // Group commands with a new router.
 // The middleware from the parent router is copied to the new router.
 func (c *CommandRouter) Group(cb func(r *CommandRouter)) {

router_test.go

@@ -232,6 +232,48 @@ func TestCommandRouter_Group(t *testing.T) {
 	})
 }
 
+func TestCommandRouter_SubGroup(t *testing.T) {
+	t.Run("can group commands with a new middleware stack", func(t *testing.T) {
+		r := clir.NewCommandRouter()
+
+		m1 := newMiddleware(t, "m1")
+		m2 := newMiddleware(t, "m2")
+
+		r.Use(m1)
+
+		r.SubGroup("party", func(r *clir.CommandRouter) {
+			r.Use(m2)
+
+			r.SubFunc("", func(ctx clir.Context) error {
+				ctx.Println("party root")
+				return nil
+			})
+
+			r.SubFunc("list", func(ctx clir.Context) error {
+				ctx.Println("party list")
+				return nil
+			})
+		})
+
+		var b strings.Builder
+		err := r.Run(clir.Context{
+			Args: []string{"party"},
+			Out:  &b,
+		})
+		is.NotError(t, err)
+		is.Equal(t, "m1\nm2\nparty root\n", b.String())
+
+		b.Reset()
+
+		err = r.Run(clir.Context{
+			Args: []string{"party", "list"},
+			Out:  &b,
+		})
+		is.NotError(t, err)
+		is.Equal(t, "m1\nm2\nparty list\n", b.String())
+	})
+}
+
 func newMiddleware(t *testing.T, name string) clir.Middleware {
 	return func(next clir.Command) clir.Command {
 		return clir.CommandFunc(func(ctx clir.Context) error {