Render using a scrolling buffer

CHANGELOG.md

@@ -55,7 +55,6 @@ This release aims to make the code a bit cleaner, fix a couple of bugs and provi
 - Rename `prompt.OptionPrefixBackgroundColor` to `prompt.WithPrefixBackgroundColor`
 - Rename `prompt.OptionInputTextColor` to `prompt.WithInputTextColor`
 - Rename `prompt.OptionInputBGColor` to `prompt.WithInputBGColor`
-- Rename `prompt.OptionPreviewSuggestionTextColor` to `prompt.WithPreviewSuggestionTextColor`
 - Rename `prompt.OptionSuggestionTextColor` to `prompt.WithSuggestionTextColor`
 - Rename `prompt.OptionSuggestionBGColor` to `prompt.WithSuggestionBGColor`
 - Rename `prompt.OptionSelectedSuggestionTextColor` to `prompt.WithSelectedSuggestionTextColor`
@@ -75,6 +74,8 @@ This release aims to make the code a bit cleaner, fix a couple of bugs and provi
 - Rename `prompt.OptionShowCompletionAtStart` to `prompt.WithShowCompletionAtStart`
 - Rename `prompt.OptionBreakLineCallback` to `prompt.WithBreakLineCallback`
 - Rename `prompt.OptionExitChecker` to `prompt.WithExitChecker`
+- Change the signature of `Completer` from `func(Document) []Suggest` to `func(Document) (suggestions []Suggest, startChar, endChar istrings.RuneNumber)`
+- Change the signature of `KeyBindFunc` from `func(*Buffer)` to `func(p *Prompt) (rerender bool)`
 
 ### Fixed
 
@@ -86,7 +87,8 @@ This release aims to make the code a bit cleaner, fix a couple of bugs and provi
 ### Removed
 
 - `prompt.SwitchKeyBindMode`
-
+- `prompt.OptionPreviewSuggestionTextColor`
+- `prompt.OptionPreviewSuggestionBGColor`
 
 ## [0.2.6] - 2021-03-03
 

_example/even-lexer/main.go

@@ -2,9 +2,10 @@ package main
 
 import (
  "fmt"
- "strings"
+ "unicode/utf8"
 
  "github.com/elk-language/go-prompt"
+ "github.com/elk-language/go-prompt/strings"
 )
 
 func main() {
@@ -19,17 +20,16 @@ func main() {
 func lexer(line string) []prompt.Token {
  var elements []prompt.Token
 
- strArr := strings.Split(line, "")
-
- for i, value := range strArr {
+ for i, value := range line {
  var color prompt.Color
  // every even char must be green.
  if i%2 == 0 {
  color = prompt.Green
  } else {
  color = prompt.White
  }
- element := prompt.NewSimpleToken(color, value)
+ lastByteIndex := strings.ByteNumber(i + utf8.RuneLen(value) - 1)
+ element := prompt.NewSimpleToken(color, lastByteIndex)
 
  elements = append(elements, element)
  }

_example/exec-command/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+ "fmt"
  "os"
  "os/exec"
 
@@ -9,6 +10,7 @@ import (
 
 func executor(t string) {
  if t != "bash" {
+ fmt.Println("Sorry, I don't understand.")
  return
  }
 
@@ -19,16 +21,9 @@ func executor(t string) {
  cmd.Run()
 }
 
-func completer(t prompt.Document) []prompt.Suggest {
- return []prompt.Suggest{
- {Text: "bash"},
- }
-}
-
 func main() {
  p := prompt.New(
  executor,
- prompt.WithCompleter(completer),
  )
  p.Run()
 }

_example/http-prompt/main.go

@@ -11,6 +11,7 @@ import (
  "strings"
 
  prompt "github.com/elk-language/go-prompt"
+ istrings "github.com/elk-language/go-prompt/strings"
 )
 
 type RequestContext struct {
@@ -157,12 +158,14 @@ func executor(in string) {
  }
 }
 
-func completer(in prompt.Document) []prompt.Suggest {
+func completer(in prompt.Document) ([]prompt.Suggest, istrings.RuneNumber, istrings.RuneNumber) {
+ endIndex := in.CurrentRuneIndex()
  w := in.GetWordBeforeCursor()
  if w == "" {
- return []prompt.Suggest{}
+ return []prompt.Suggest{}, 0, 0
  }
- return prompt.FilterHasPrefix(suggestions, w, true)
+ startIndex := endIndex - istrings.RuneCount(w)
+ return prompt.FilterHasPrefix(suggestions, w, true), startIndex, endIndex
 }
 
 func main() {

_example/live-prefix/main.go

@@ -4,6 +4,7 @@ import (
  "fmt"
 
  prompt "github.com/elk-language/go-prompt"
+ istrings "github.com/elk-language/go-prompt/strings"
 )
 
 var LivePrefix string = ">>> "
@@ -17,14 +18,18 @@ func executor(in string) {
  LivePrefix = in + "> "
 }
 
-func completer(in prompt.Document) []prompt.Suggest {
+func completer(in prompt.Document) ([]prompt.Suggest, istrings.RuneNumber, istrings.RuneNumber) {
+ endIndex := in.CurrentRuneIndex()
+ w := in.GetWordBeforeCursor()
+ startIndex := endIndex - istrings.RuneCount(w)
+
  s := []prompt.Suggest{
  {Text: "users", Description: "Store the username and age"},
  {Text: "articles", Description: "Store the article text posted by user"},
  {Text: "comments", Description: "Store the text commented to articles"},
  {Text: "groups", Description: "Combine users with specific rules"},
  }
- return prompt.FilterHasPrefix(s, in.GetWordBeforeCursor(), true)
+ return prompt.FilterHasPrefix(s, w, true), startIndex, endIndex
 }
 
 func changeLivePrefix() string {

buffer.go

@@ -11,6 +11,7 @@ import (
 type Buffer struct {
  workingLines []string // The working lines. Similar to history
  workingIndex int // index of the current line
+ startLine int // Line number of the first visible line in the terminal (0-indexed)
  cursorPosition istrings.RuneNumber
  cacheDocument *Document
  lastKeyStroke Key
@@ -41,8 +42,18 @@ func (b *Buffer) DisplayCursorPosition(columns istrings.Width) Position {
  return b.Document().DisplayCursorPosition(columns)
 }
 
-// InsertText insert string from current line.
-func (b *Buffer) InsertText(text string, overwrite bool, moveCursor bool) {
+// Insert string into the buffer and move the cursor.
+func (b *Buffer) InsertTextMoveCursor(text string, columns istrings.Width, rows int, overwrite bool) {
+ b.insertText(text, columns, rows, overwrite, true)
+}
+
+// Insert string into the buffer without moving the cursor.
+func (b *Buffer) InsertText(text string, overwrite bool) {
+ b.insertText(text, 0, 0, overwrite, false)
+}
+
+// insertText insert string from current line.
+func (b *Buffer) insertText(text string, columns istrings.Width, rows int, overwrite bool, moveCursor bool) {
  currentTextRunes := []rune(b.Text())
  cursor := b.cursorPosition
 
@@ -54,22 +65,52 @@ func (b *Buffer) InsertText(text string, overwrite bool, moveCursor bool) {
  if i := strings.IndexAny(overwritten, "\n"); i != -1 {
  overwritten = overwritten[:i]
  }
- b.setText(string(currentTextRunes[:cursor]) + text + string(currentTextRunes[cursor+istrings.RuneCount(overwritten):]))
+ b.setText(
+ string(currentTextRunes[:cursor])+text+string(currentTextRunes[cursor+istrings.RuneCount(overwritten):]),
+ columns,
+ rows,
+ )
  } else {
- b.setText(string(currentTextRunes[:cursor]) + text + string(currentTextRunes[cursor:]))
+ b.setText(
+ string(currentTextRunes[:cursor])+text+string(currentTextRunes[cursor:]),
+ columns,
+ rows,
+ )
  }
 
  if moveCursor {
  b.cursorPosition += istrings.RuneCount(text)
+ b.RecalculateStartLine(columns, rows)
+ }
+}
+
+func (b *Buffer) ResetStartLine() {
+ b.startLine = 0
+}
+
+// Calculates the startLine once again and returns true when it's been changed.
+func (b *Buffer) RecalculateStartLine(columns istrings.Width, rows int) bool {
+ origStartLine := b.startLine
+ pos := b.DisplayCursorPosition(columns)
+ if pos.Y > b.startLine+rows-1 {
+ b.startLine = pos.Y - rows + 1
+ } else if pos.Y < b.startLine {
+ b.startLine = pos.Y
+ }
+
+ if b.startLine < 0 {
+ b.startLine = 0
  }
+ return origStartLine != b.startLine
 }
 
 // SetText method to set text and update cursorPosition.
 // (When doing this, make sure that the cursor_position is valid for this text.
 // text/cursor_position should be consistent at any time, otherwise set a Document instead.)
-func (b *Buffer) setText(text string) {
+func (b *Buffer) setText(text string, col istrings.Width, row int) {
  debug.Assert(b.cursorPosition <= istrings.RuneCount(text), "length of input should be shorter than cursor position")
  b.workingLines[b.workingIndex] = text
+ b.RecalculateStartLine(col, row)
 }
 
 // Set cursor position. Return whether it changed.
@@ -81,40 +122,49 @@ func (b *Buffer) setCursorPosition(p istrings.RuneNumber) {
  }
 }
 
-func (b *Buffer) setDocument(d *Document) {
+func (b *Buffer) setDocument(d *Document, columns istrings.Width, rows int) {
  b.cacheDocument = d
  b.setCursorPosition(d.cursorPosition) // Call before setText because setText check the relation between cursorPosition and line length.
- b.setText(d.Text)
+ b.setText(d.Text, columns, rows)
+ b.RecalculateStartLine(columns, rows)
 }
 
-// CursorLeft move to left on the current line.
-func (b *Buffer) CursorLeft(count istrings.RuneNumber) {
+// Move to the left on the current line.
+// Returns true when the view should be rerendered.
+func (b *Buffer) CursorLeft(count istrings.RuneNumber, columns istrings.Width, rows int) bool {
  l := b.Document().GetCursorLeftPosition(count)
  b.cursorPosition += l
+ return b.RecalculateStartLine(columns, rows)
 }
 
-// CursorRight move to right on the current line.
-func (b *Buffer) CursorRight(count istrings.RuneNumber) {
+// Move to the right on the current line.
+// Returns true when the view should be rerendered.
+func (b *Buffer) CursorRight(count istrings.RuneNumber, columns istrings.Width, rows int) bool {
  l := b.Document().GetCursorRightPosition(count)
  b.cursorPosition += l
+ return b.RecalculateStartLine(columns, rows)
 }
 
 // CursorUp move cursor to the previous line.
 // (for multi-line edit).
-func (b *Buffer) CursorUp(count int) {
+// Returns true when the view should be rerendered.
+func (b *Buffer) CursorUp(count int, columns istrings.Width, rows int) bool {
  orig := b.Document().CursorPositionCol()
  b.cursorPosition += b.Document().GetCursorUpPosition(count, orig)
+ return b.RecalculateStartLine(columns, rows)
 }
 
 // CursorDown move cursor to the next line.
 // (for multi-line edit).
-func (b *Buffer) CursorDown(count int) {
+// Returns true when the view should be rerendered.
+func (b *Buffer) CursorDown(count int, columns istrings.Width, rows int) bool {
  orig := b.Document().CursorPositionCol()
  b.cursorPosition += b.Document().GetCursorDownPosition(count, orig)
+ return b.RecalculateStartLine(columns, rows)
 }
 
 // DeleteBeforeCursor delete specified number of characters before cursor and return the deleted text.
-func (b *Buffer) DeleteBeforeCursor(count istrings.RuneNumber) (deleted string) {
+func (b *Buffer) DeleteBeforeCursor(count istrings.RuneNumber, columns istrings.Width, rows int) (deleted string) {
  debug.Assert(count >= 0, "count should be positive")
  r := []rune(b.Text())
 
@@ -127,28 +177,32 @@ func (b *Buffer) DeleteBeforeCursor(count istrings.RuneNumber) (deleted string)
  b.setDocument(&Document{
  Text: string(r[:start]) + string(r[b.cursorPosition:]),
  cursorPosition: b.cursorPosition - istrings.RuneNumber(len([]rune(deleted))),
- })
+ }, columns, rows)
  }
  return
 }
 
 // NewLine means CR.
-func (b *Buffer) NewLine(copyMargin bool) {
+func (b *Buffer) NewLine(columns istrings.Width, rows int, copyMargin bool) {
  if copyMargin {
- b.InsertText("\n"+b.Document().leadingWhitespaceInCurrentLine(), false, true)
+ b.InsertTextMoveCursor("\n"+b.Document().leadingWhitespaceInCurrentLine(), columns, rows, false)
  } else {
- b.InsertText("\n", false, true)
+ b.InsertTextMoveCursor("\n", columns, rows, false)
  }
 }
 
 // Delete specified number of characters and Return the deleted text.
-func (b *Buffer) Delete(count istrings.RuneNumber) string {
+func (b *Buffer) Delete(count istrings.RuneNumber, col istrings.Width, row int) string {
  r := []rune(b.Text())
  if b.cursorPosition < istrings.RuneNumber(len(r)) {
  textAfterCursor := b.Document().TextAfterCursor()
  textAfterCursorRunes := []rune(textAfterCursor)
  deletedRunes := textAfterCursorRunes[:count]
- b.setText(string(r[:b.cursorPosition]) + string(r[b.cursorPosition+istrings.RuneNumber(len(deletedRunes)):]))
+ b.setText(
+ string(r[:b.cursorPosition])+string(r[b.cursorPosition+istrings.RuneNumber(len(deletedRunes)):]),
+ col,
+ row,
+ )
 
  deleted := string(deletedRunes)
  return deleted
@@ -158,21 +212,29 @@ func (b *Buffer) Delete(count istrings.RuneNumber) string {
 }
 
 // JoinNextLine joins the next line to the current one by deleting the line ending after the current line.
-func (b *Buffer) JoinNextLine(separator string) {
+func (b *Buffer) JoinNextLine(separator string, col istrings.Width, row int) {
  if !b.Document().OnLastLine() {
  b.cursorPosition += b.Document().GetEndOfLinePosition()
- b.Delete(1)
+ b.Delete(1, col, row)
  // Remove spaces
- b.setText(b.Document().TextBeforeCursor() + separator + strings.TrimLeft(b.Document().TextAfterCursor(), " "))
+ b.setText(
+ b.Document().TextBeforeCursor()+separator+strings.TrimLeft(b.Document().TextAfterCursor(), " "),
+ col,
+ row,
+ )
  }
 }
 
 // SwapCharactersBeforeCursor swaps the last two characters before the cursor.
-func (b *Buffer) SwapCharactersBeforeCursor() {
+func (b *Buffer) SwapCharactersBeforeCursor(col istrings.Width, row int) {
  if b.cursorPosition >= 2 {
  x := b.Text()[b.cursorPosition-2 : b.cursorPosition-1]
  y := b.Text()[b.cursorPosition-1 : b.cursorPosition]
- b.setText(b.Text()[:b.cursorPosition-2] + y + x + b.Text()[b.cursorPosition:])
+ b.setText(
+ b.Text()[:b.cursorPosition-2]+y+x+b.Text()[b.cursorPosition:],
+ col,
+ row,
+ )
  }
 }
 
@@ -181,6 +243,7 @@ func NewBuffer() (b *Buffer) {
  b = &Buffer{
  workingLines: []string{""},
  workingIndex: 0,
+ startLine: 0,
  }
  return
 }