Info Window

_example/info-window-fixed/main.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	prompt "github.com/c-bata/go-prompt"
+)
+
+var infoWindow *prompt.FixedInfoWindow
+var p *prompt.Prompt
+
+func printInfo() {
+	infoWindow.Clear()
+	l1 := infoWindow.RequestLine(0)
+	*l1 = string("Hallo Line 1")
+	p.UpdateInfoWindow(infoWindow)
+}
+
+func executor(t string) {
+	if t == "info" {
+		go printInfo()
+	}
+	return
+}
+
+func completer(t prompt.Document) []prompt.Suggest {
+	return []prompt.Suggest{
+		{Text: "info"},
+	}
+}
+
+func main() {
+	infoWindow = prompt.NewFixedInfoWindow(20)
+	p = prompt.New(
+		executor,
+		completer,
+		prompt.OptionInfoWindowHeight(30),
+	)
+	p.UpdateInfoWindow(infoWindow)
+	p.Run()
+}

_example/info-window-linear/main.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	prompt "github.com/c-bata/go-prompt"
+)
+
+var infoWindow *prompt.LinearInfoWindow
+var p *prompt.Prompt
+
+func printInfo() {
+	infoWindow.AddLine("Test info")
+	p.UpdateInfoWindow(infoWindow)
+}
+
+func executor(t string) {
+	if t == "info" {
+		go printInfo()
+	}
+	return
+}
+
+func completer(t prompt.Document) []prompt.Suggest {
+	return []prompt.Suggest{
+		{Text: "info"},
+	}
+}
+
+func main() {
+	infoWindow = prompt.NewLinearInfoWindow(100, true)
+	p = prompt.New(
+		executor,
+		completer,
+		prompt.OptionInfoWindowHeight(30),
+	)
+	p.UpdateInfoWindow(infoWindow)
+	p.Run()
+}

fixed_info_window.go

@@ -0,0 +1,70 @@
+package prompt
+
+// FixedInfoWindow is the info window that
+// uses fixed number of lines and is not scrollable
+type FixedInfoWindow struct {
+	lines    []*string
+	maxLines int
+	InfoWindow
+}
+
+// GetLines returns an array of the Lines from the info window
+// count tells how many lines should be returned
+func (l *FixedInfoWindow) GetLines(count int) []string {
+	ret := []string{}
+
+	if count >= len(l.lines) {
+		for i := 0; i < len(l.lines); i++ {
+			ret = append(ret, *l.lines[i])
+		}
+	} else {
+		for i := 0; i < count; i++ {
+			ret = append(ret, *l.lines[i])
+		}
+	}
+	return ret
+}
+
+// RequestLine will return a pointer to one specific line
+// which can be updated to new content
+func (l *FixedInfoWindow) RequestLine(line int) *string {
+	if line < 0 || line > l.maxLines-1 {
+		return nil
+	}
+	return l.lines[line]
+}
+
+// Clear cleans the whole info window
+func (l *FixedInfoWindow) Clear() {
+	for _, l := range l.lines {
+		*l = ""
+	}
+}
+
+// ClearLine will clear one specific line of the info window
+func (l *FixedInfoWindow) ClearLine(line int) {
+	if line < 0 || line >= len(l.lines) {
+		return
+	}
+
+	l.lines[line] = new(string)
+}
+
+// Len returns the number of lines that the info window
+// can print
+func (l *FixedInfoWindow) Len() int {
+	return l.maxLines
+}
+
+// NewFixedInfoWindow will create a new fixed size info window
+// with the number of lines given by the lines parameter
+func NewFixedInfoWindow(lines int) *FixedInfoWindow {
+	ret := new(FixedInfoWindow)
+	ret.lines = []*string{}
+	ret.maxLines = lines
+	for i := 0; i < ret.maxLines; i++ {
+		ret.lines = append(ret.lines, new(string))
+	}
+
+	return ret
+}

go.mod

@@ -8,3 +8,5 @@ require (
 	github.com/pkg/term v0.0.0-20180423043932-cda20d4ac917
 	golang.org/x/sys v0.0.0-20180620133508-ad87a3a340fa
 )
+
+go 1.13

info_window.go

@@ -0,0 +1,8 @@
+package prompt
+
+// InfoWindow is the interface that needs
+// to be implemented by new types of information
+// windows
+type InfoWindow interface {
+	GetLines(int) []string
+}

linear_info_window.go

@@ -0,0 +1,84 @@
+package prompt
+
+// LinearInfoWindow is the info window that
+// is scrollable and can be used to have a
+// linear output information
+type LinearInfoWindow struct {
+	lines      []string
+	maxLines   int
+	actLine    int
+	autoscroll bool
+	InfoWindow
+}
+
+// GetLines returns an array of the Lines from the info window
+// count tells how many lines should be returned
+func (l *LinearInfoWindow) GetLines(count int) []string {
+	if l.actLine < 0 || l.actLine >= len(l.lines) {
+		return []string{}
+	}
+
+	if l.actLine+count >= len(l.lines) {
+		if len(l.lines)-(count+1) >= 0 {
+			return l.lines[len(l.lines)-(count):]
+		}
+		return l.lines
+	}
+
+	return l.lines[l.actLine : l.actLine+count]
+}
+
+// AddLine will append a new line to the info window
+func (l *LinearInfoWindow) AddLine(line string) {
+	if l.maxLines != 0 {
+		if len(l.lines) >= l.maxLines {
+			l.lines = l.lines[1 : len(l.lines)-1]
+		}
+	}
+	l.lines = append(l.lines, line)
+	if l.autoscroll {
+		l.LineDown()
+	}
+}
+
+// LineUp will scroll up a line
+func (l *LinearInfoWindow) LineUp() {
+	if l.actLine > 0 {
+		l.actLine--
+	}
+}
+
+// LineDown will scroll down a line
+func (l *LinearInfoWindow) LineDown() {
+	if l.actLine < len(l.lines)-1 {
+		l.actLine++
+	}
+}
+
+// Clear cleans the whole info window
+func (l *LinearInfoWindow) Clear() {
+	l.lines = []string{}
+	l.actLine = 0
+}
+
+// ClearLine will clear one specific line of the info window
+func (l *LinearInfoWindow) ClearLine(line int) {
+	if line < 0 || line >= len(l.lines) {
+		return
+	}
+
+	l.lines = append(l.lines[:line], l.lines[line+1:]...)
+}
+
+// NewLinearInfoWindow will create a new info window that is scrollable
+// with the maximum number of lines give by the parameter maxLines
+// If autoscroll is set to true it will scroll up when adding lines
+func NewLinearInfoWindow(maxLines int, autoscroll bool) *LinearInfoWindow {
+	ret := new(LinearInfoWindow)
+	ret.actLine = 0
+	ret.maxLines = maxLines
+	ret.autoscroll = autoscroll
+	ret.lines = []string{}
+
+	return ret
+}

option.go

@@ -181,6 +181,14 @@ func OptionScrollbarBGColor(x Color) Option {
 	}
 }
 
+// OptionInfoWindowHeight to enable or change the size of the info window.
+func OptionInfoWindowHeight(x uint16) Option {
+	return func(p *Prompt) error {
+		p.renderer.infoWindowHeight = x
+		return nil
+	}
+}
+
 // OptionMaxSuggestion specify the max number of displayed suggestions.
 func OptionMaxSuggestion(x uint16) Option {
 	return func(p *Prompt) error {

prompt.go

@@ -245,6 +245,11 @@ func (p *Prompt) Input() string {
 	}
 }
 
+// UpdateInfoWindow update info window if enabled
+func (p *Prompt) UpdateInfoWindow(i InfoWindow) {
+	p.renderer.RenderInfoWindow(i)
+}
+
 func (p *Prompt) readBuffer(bufCh chan []byte, stopCh chan struct{}) {
 	debug.Log("start reading buffer")
 	for {

render.go

@@ -2,6 +2,7 @@ package prompt
 
 import (
 	"runtime"
+	"sync"
 
 	"github.com/c-bata/go-prompt/internal/debug"
 	runewidth "github.com/mattn/go-runewidth"
@@ -19,6 +20,10 @@ type Render struct {
 
 	previousCursor int
 
+	// info window
+	infoWindowHeight uint16
+	lock             sync.Mutex
+
 	// colors,
 	prefixTextColor              Color
 	prefixBGColor                Color
@@ -78,6 +83,38 @@ func (r *Render) prepareArea(lines int) {
 	return
 }
 
+// RenderInfoWindow renders the info window to console
+func (r *Render) RenderInfoWindow(i InfoWindow) {
+	if r.infoWindowHeight > 0 {
+		r.lock.Lock()
+		defer r.lock.Unlock()
+		r.out.SaveCursor()
+		r.out.CursorGoTo(1, 0)
+		lines := i.GetLines(int(r.infoWindowHeight))
+		count := len(lines)
+		if count > int(r.infoWindowHeight) {
+			count = int(r.infoWindowHeight)
+		}
+		j := 1
+		for i := 0; i < count; i++ {
+			r.out.CursorGoTo(j, 0)
+			if len(lines[i]) > int(r.col) {
+				r.out.WriteStr(lines[i][:r.col+1])
+			} else {
+				r.out.WriteStr(lines[i])
+			}
+			r.out.EraseEndOfLine()
+			j++
+		}
+		for ; j <= int(r.infoWindowHeight); j++ {
+			r.out.CursorGoTo(j, 0)
+			r.out.EraseEndOfLine()
+		}
+		defer func() { debug.AssertNoError(r.out.Flush()) }()
+		r.out.UnSaveCursor()
+	}
+}
+
 // UpdateWinSize called when window size is changed.
 func (r *Render) UpdateWinSize(ws *WinSize) {
 	r.row = ws.Row
@@ -180,6 +217,13 @@ func (r *Render) Render(buffer *Buffer, completion *CompletionManager) {
 	defer func() { debug.AssertNoError(r.out.Flush()) }()
 	r.move(r.previousCursor, 0)
 
+	// info window
+	if r.infoWindowHeight > 0 {
+		r.lock.Lock()
+		defer r.lock.Unlock()
+		r.out.CursorGoTo(int(r.infoWindowHeight+1), 0)
+	}
+
 	line := buffer.Text()
 	prefix := r.getCurrentPrefix()
 	cursor := runewidth.StringWidth(prefix) + runewidth.StringWidth(line)