Implemented the new way of thinking about ScreenIds. As PATHS.

cmd/test/main.go

@@ -27,7 +27,7 @@ func NewMutateMessageWidget(fn func(string) string) *MutateMessageWidget {
 }
 
 func (w *MutateMessageWidget) Serve(c *tg.Context) {
-	args, ok := c.Arg.([]any)
+	args, ok := c.Arg.(tg.ArgSlice)
 	if ok {
 		for _, arg := range args {
 			c.Sendf("%v", arg)
@@ -51,8 +51,9 @@ func ExtractSessionData(c *tg.Context) *SessionData {
 }
 
 var (
-	startScreenButton = tg.NewButton("🏠 To the start screen").
+	startScreenButton = tg.NewButton("Back").ActionFunc(func(c *tg.Context){
-				ScreenChange("/start")
+		c.GoUp()
+	})
 
 	incDecKeyboard = tg.NewKeyboard().Row(
 		tg.NewButton("+").ActionFunc(func(c *tg.Context) {
@@ -73,7 +74,7 @@ var (
 		tg.NewButton("Inc/Dec").ScreenChange("/start/inc-dec"),
 	).Row(
 		tg.NewButton("Upper case").ActionFunc(func(c *tg.Context){
-			c.ChangeScreen("/start/upper-case", "this shit", "works")
+			c.Go("/start/upper-case", "this shit", "works")
 		}),
 		tg.NewButton("Lower case").ScreenChange("/start/lower-case"),
 	).Row(
@@ -175,7 +176,7 @@ var beh = tg.NewBehaviour().
 			Desc("start or restart the bot or move to the start screen").
 			ActionFunc(func(c *tg.Context){
 				c.Sendf("Your username is %q", c.Message.From.UserName)
-				c.ChangeScreen("/start")
+				c.Go("/start")
 			}),
 		tg.NewCommand("hello").
 			Desc("sends the 'Hello, World!' message back").

tg/command.go

@@ -165,7 +165,7 @@ func (widget *CommandWidget) Serve(c *Context) {
 
 	var cmdUpdates *UpdateChan
 	for u := range c.Input() {
-		if c.ScreenId() == "" && u.Message != nil {
+		if c.CurScreen() == "" && u.Message != nil {
 			// Skipping and executing the preinit action
 			// while we have the empty screen.
 			// E. g. the session did not start.

tg/page.go

@@ -92,7 +92,7 @@ func (p *Page) Serve(c *Context) {
 	msgs, _ := c.Render(p)
 	inlineMsg := msgs["page/inline"]
 
-	subUpdates := c.RunWidget(p.SubWidget)
+	subUpdates := c.RunWidget(p.SubWidget, c.Arg)
 	defer subUpdates.Close()
 
 	inlineUpdates := c.RunWidget(p.Inline)

tg/private.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 
 	//tgbotapi "github.com/go-telegram-bot-api/telegram-bot-api/v5"
+	"path"
 )
 
 type ContextType string
@@ -41,11 +42,11 @@ func (c *context) run(a Action, u *Update) {
 	a.Act(&Context{context: c, Update:  u})
 }
 
-func (c *Context) ScreenId() ScreenId {
+func (c *Context) CurScreen() ScreenId {
 	return c.screenId
 }
 
-func (c *Context) PrevScreenId() ScreenId {
+func (c *Context) PrevScreen() ScreenId {
 	return c.prevScreenId
 }
 
@@ -149,7 +150,7 @@ func (sc ScreenChange) Act(c *Context) {
 	if !c.Bot.behaviour.ScreenExist(ScreenId(sc)) {
 		panic(ScreenNotExistErr)
 	}
-	err := c.ChangeScreen(ScreenId(sc))
+	err := c.Go(ScreenId(sc))
 	if err != nil {
 		panic(err)
 	}
@@ -158,7 +159,7 @@ func (sc ScreenChange) Act(c *Context) {
 type C = Context
 
 // Changes screen of user to the Id one.
-func (c *Context) ChangeScreen(screenId ScreenId, args ...any) error {
+func (c *Context) Go(screenId ScreenId, args ...any) error {
 	if !c.Bot.behaviour.ScreenExist(screenId) {
 		return ScreenNotExistErr
 	}
@@ -171,9 +172,8 @@ func (c *Context) ChangeScreen(screenId ScreenId, args ...any) error {
 
 	// Stopping the current widget.
 	c.skippedUpdates.Close()
-	c.skippedUpdates = nil
 	if screen.Widget != nil {
-		c.skippedUpdates = c.RunWidget(screen.Widget, args)
+		c.skippedUpdates = c.RunWidget(screen.Widget, args...)
 	} else {
 		panic("no widget defined for the screen")
 	}
@@ -187,7 +187,6 @@ func (c *Context) RunWidget(widget Widget, args ...any) *UpdateChan {
 		return nil
 	}
 
-
 	var arg any
 	if len(args) == 1 {
 		arg = args[0]
@@ -202,12 +201,20 @@ func (c *Context) RunWidget(widget Widget, args ...any) *UpdateChan {
 				WithInput(updates).
 				WithArg(arg),
 		)
+		// To let widgets finish themselves before
+		// the channel is closed.
 		updates.Close()
 	}()
 
 	return updates
 }
 
-func (c *Context) ChangeToPrevScreen() {
+func (c *Context) GoUp() {
-	c.ChangeScreen(c.PrevScreenId())
+	c.Go(ScreenId(path.Dir(string(c.CurScreen()))))
+}
+
+// Change screen to the previous.
+// To get to the parent screen use GoUp.
+func (c *Context) GoPrev() {
+	c.Go(c.PrevScreen())
 }

tg/widget.go

@@ -5,6 +5,10 @@ import (
 	//"fmt"
 )
 
+type ArgMap = map[string] any
+type ArgSlice = []any
+type ArgList[V any] []V
+
 // Implementing the interface provides
 // ability to build your own widgets,
 // aka components.