refactor repl

engine/repl.go

@@ -15,11 +15,11 @@ func (g *Game) REPL(src io.Reader, dst io.Writer, assets fs.FS) error {
 	fmt.Fprint(dst, "game>")
 	sc := bufio.NewScanner(src)
 	for sc.Scan() {
-		tok := strings.Split(sc.Text(), " ")
-		if len(tok) == 0 {
+		argv := strings.Split(sc.Text(), " ")
+		if len(argv) == 0 {
 			continue
 		}
-		switch tok[0] {
+		switch argv[0] {
 		case "quit":
 			os.Exit(0)
 		case "pause":
@@ -27,62 +27,68 @@ func (g *Game) REPL(src io.Reader, dst io.Writer, assets fs.FS) error {
 		case "resume", "unpause":
 			g.Enable()
 		case "save":
-			if len(tok) != 2 {
-				fmt.Fprintln(dst, "Usage: save ID")
-				break
+			g.cmdSave(dst, argv)
+		case "reload":
+			g.cmdReload(dst, assets)
+		case "tree":
+			g.cmdTree(dst, argv)
 		}
-			id := tok[1]
+		fmt.Fprint(dst, "game>")
+	}
+	return sc.Err()
+}
+
+func (g *Game) cmdSave(dst io.Writer, argv []string) {
+	if len(argv) != 2 {
+		fmt.Fprintln(dst, "Usage: save ID")
+		return
+	}
+	id := argv[1]
 	c := g.Component(id)
 	if c == nil {
 		fmt.Fprintf(dst, "Component %q not found\n", id)
-				break
+		return
 	}
 	s, ok := c.(Saver)
 	if !ok {
 		fmt.Fprintf(dst, "Component %q not a Saver (type %T)\n", id, c)
-				break
+		return
 	}
 	if err := s.Save(); err != nil {
 		fmt.Fprintf(dst, "Couldn't save %q: %v\n", id, err)
 	}
-		case "reload":
+}
+
+func (g *Game) cmdReload(dst io.Writer, assets fs.FS) {
 	g.Disable()
 	g.Hide()
 	if err := g.Load(assets); err != nil {
 		fmt.Fprintf(dst, "Couldn't load: %v\n", err)
-				break
+		return
 	}
 	g.Prepare()
 	g.Enable()
 	g.Show()
-		case "tree":
-			if len(tok) < 1 || len(tok) > 2 {
+}
+
+func (g *Game) cmdTree(dst io.Writer, argv []string) {
+	if len(argv) < 1 || len(argv) > 2 {
 		fmt.Println(dst, "Usage: tree [ID]")
 	}
 	var c interface{} = g
-			if len(tok) == 2 {
-				// subtree
-				id := tok[1]
+	if len(argv) == 2 { // subtree
+		id := argv[1]
 		c = g.Component(id)
 		if c == nil {
 			fmt.Fprintf(dst, "Component %q not found\n", id)
-					break
+			return
 		}
 	}
-			type item struct {
-				c     interface{}
-				depth int
-			}
-			stack := []item{{c, 0}}
-			for len(stack) > 0 {
-				tail := len(stack) - 1
-				x := stack[tail]
-				stack = stack[:tail]
-				c := x.c
-
+	var walk func(interface{}, int)
+	walk = func(c interface{}, depth int) {
 		indent := ""
-				if x.depth > 0 {
-					indent = strings.Repeat("  ", x.depth-1) + "↳ "
+		if depth > 0 {
+			indent = strings.Repeat("  ", depth-1) + "↳ "
 		}
 		i, ok := c.(Identifier)
 		if ok {
@@ -90,15 +96,11 @@ func (g *Game) REPL(src io.Reader, dst io.Writer, assets fs.FS) error {
 		} else {
 			fmt.Fprintf(dst, "%s%T\n", indent, c)
 		}
-
 		if s, ok := c.(Scanner); ok {
-					for _, y := range s.Scan() {
-						stack = append(stack, item{y, x.depth + 1})
+			for _, d := range s.Scan() {
+				walk(d, depth+1)
 			}
 		}
 	}
-		}
-		fmt.Fprint(dst, "game>")
-	}
-	return sc.Err()
+	walk(c, 0)
 }