More work on readline

tools/cmd/at/shell.go

@@ -8,6 +8,7 @@ import (
 	"kitty/tools/cli"
 	"kitty/tools/cli/markup"
 	"kitty/tools/tui/loop"
+	"kitty/tools/tui/readline"
 )
 
 var _ = fmt.Print
@@ -21,11 +22,18 @@ func shell_loop(kill_if_signaled bool) (int, error) {
 	if err != nil {
 		return 1, err
 	}
+	rl := readline.New(lp, readline.RlInit{Prompt: prompt})
+
 	lp.OnInitialize = func() (string, error) {
-		lp.QueueWriteString(prompt)
+		rl.Start()
 		return "\r\n", nil
 	}
 
+	lp.OnResumeFromStop = func() error {
+		rl.Start()
+		return nil
+	}
+
 	err = lp.Run()
 	if err != nil {
 		return 1, err

tools/tui/loop/api.go

@@ -193,6 +193,40 @@ func (self *Loop) Beep() {
 	self.QueueWriteString("\a")
 }
 
+func (self *Loop) StartAtomicUpdate() {
+	self.QueueWriteString(PENDING_UPDATE.EscapeCodeToSet())
+}
+
+func (self *Loop) EndAtomicUpdate() {
+	self.QueueWriteString(PENDING_UPDATE.EscapeCodeToReset())
+}
+
+func (self *Loop) SetCursorShape(shape CursorShapes, blink bool) {
+	self.QueueWriteString(CursorShape(shape, blink))
+}
+
+func (self *Loop) MoveCursorHorizontally(amt int) {
+	suffix := "C"
+	if amt < 0 {
+		suffix = "D"
+		amt *= -1
+	}
+	self.QueueWriteString(fmt.Sprintf("\x1b[%d%s", amt, suffix))
+}
+
+func (self *Loop) MoveCursorVertically(amt int) {
+	suffix := "B"
+	if amt < 0 {
+		suffix = "A"
+		amt *= -1
+	}
+	self.QueueWriteString(fmt.Sprintf("\x1b[%d%s", amt, suffix))
+}
+
+func (self *Loop) ClearToEndOfScreen() {
+	self.QueueWriteString("\x1b[J")
+}
+
 func (self *Loop) Quit(exit_code int) {
 	self.exit_code = exit_code
 	self.keep_going = false

tools/tui/loop/terminal-state.go

@@ -21,6 +21,14 @@ const (
 	CLEAR_SCREEN                  = "\033[H\033[2J"
 )
 
+type CursorShapes uint
+
+const (
+	BLOCK_CURSOR     CursorShapes = 1
+	UNDERLINE_CURSOR CursorShapes = 3
+	BAR_CURSOR       CursorShapes = 5
+)
+
 type Mode uint32
 
 const private Mode = 1 << 31
@@ -147,3 +155,10 @@ func (self *TerminalStateOptions) ResetStateEscapeCodes() string {
 	sb.WriteString(RESTORE_COLORS)
 	return sb.String()
 }
+
+func CursorShape(shape CursorShapes, blink bool) string {
+	if !blink {
+		shape += 1
+	}
+	return fmt.Sprintf("\x1b[%d q", shape)
+}

tools/tui/readline/api.go

@@ -0,0 +1,81 @@
+// License: GPLv3 Copyright: 2022, Kovid Goyal, <kovid at kovidgoyal.net>
+
+package readline
+
+import (
+	"fmt"
+
+	"kitty/tools/tui/loop"
+	"kitty/tools/wcswidth"
+)
+
+var _ = fmt.Print
+
+const ST = "\x1b\\"
+const PROMPT_MARK = "\x1b]133;"
+
+type RlInit struct {
+	Prompt                  string
+	ContinuationPrompt      string
+	EmptyContinuationPrompt bool
+	DontMarkPrompts         bool
+}
+
+type Readline struct {
+	prompt                  string
+	prompt_len              int
+	continuation_prompt     string
+	continuation_prompt_len int
+	mark_prompts            bool
+	loop                    *loop.Loop
+
+	// The number of lines after the initial line
+	cursor_y int
+	// Input lines
+	lines []string
+	// The line the cursor is at currently
+	cursor_line int
+	// The offset into the text of the cursor line
+	cursor_pos_in_line int
+}
+
+func New(loop *loop.Loop, r RlInit) *Readline {
+	ans := &Readline{
+		prompt: r.Prompt, prompt_len: wcswidth.Stringwidth(r.Prompt), mark_prompts: !r.DontMarkPrompts,
+		loop: loop, lines: []string{""},
+	}
+	if r.ContinuationPrompt != "" || !r.EmptyContinuationPrompt {
+		ans.continuation_prompt = r.ContinuationPrompt
+		if ans.continuation_prompt == "" {
+			ans.continuation_prompt = "> "
+		}
+	}
+	if ans.mark_prompts {
+		ans.prompt = PROMPT_MARK + "A" + ST + ans.prompt
+		ans.continuation_prompt = PROMPT_MARK + "A;k=s" + ST + ans.continuation_prompt
+	}
+	return ans
+}
+
+func (self *Readline) Start() {
+	self.loop.SetCursorShape(loop.BAR_CURSOR, true)
+	self.Redraw()
+}
+
+func (self *Readline) Redraw() {
+	self.loop.StartAtomicUpdate()
+	self.RedrawNonAtomic()
+	self.loop.EndAtomicUpdate()
+}
+
+func (self *Readline) RedrawNonAtomic() {
+	self.redraw()
+}
+
+func (self *Readline) End() {
+	self.loop.QueueWriteString("\r\n")
+	self.loop.SetCursorShape(loop.BLOCK_CURSOR, true)
+	if self.mark_prompts {
+		self.loop.QueueWriteString(PROMPT_MARK + "C" + ST)
+	}
+}

tools/tui/readline/draw.go

@@ -0,0 +1,58 @@
+// License: GPLv3 Copyright: 2022, Kovid Goyal, <kovid at kovidgoyal.net>
+
+package readline
+
+import (
+	"fmt"
+	"kitty/tools/wcswidth"
+)
+
+var _ = fmt.Print
+
+func (self *Readline) write_line_with_prompt(line, prompt string, screen_width int) int {
+	self.loop.QueueWriteString(prompt)
+	self.loop.QueueWriteString(line)
+	w := wcswidth.Stringwidth(prompt) + wcswidth.Stringwidth(line)
+	return w / screen_width
+}
+
+func (self *Readline) move_cursor_to_text_position(pos, screen_width int) int {
+	num_of_lines := pos / screen_width
+	if num_of_lines > 0 {
+		self.loop.MoveCursorVertically(num_of_lines)
+	}
+	self.loop.QueueWriteString("\r")
+	x := pos % screen_width
+	self.loop.MoveCursorHorizontally(x)
+	return num_of_lines
+}
+
+func (self *Readline) redraw() {
+	if self.cursor_y > 0 {
+		self.loop.MoveCursorVertically(-self.cursor_y)
+	}
+	self.loop.QueueWriteString("\r")
+	self.loop.ClearToEndOfScreen()
+	y := 0
+	line_with_cursor := 0
+	screen_size, err := self.loop.ScreenSize()
+	if err != nil {
+		screen_size.WidthCells = 80
+		screen_size.HeightCells = 24
+	}
+	for i, line := range self.lines {
+		p := self.prompt
+		if i > 0 {
+			p = self.continuation_prompt
+		}
+		num_lines := self.write_line_with_prompt(line, p, int(screen_size.WidthCells))
+		if i == self.cursor_line {
+			line_with_cursor = y
+		}
+		y += num_lines
+	}
+	self.loop.MoveCursorVertically(-y + line_with_cursor)
+	line := self.lines[self.cursor_line]
+	line_with_cursor += self.move_cursor_to_text_position(wcswidth.Stringwidth(line[:self.cursor_pos_in_line]), int(screen_size.WidthCells))
+	self.cursor_y = line_with_cursor
+}