Fix vertical cursor movement

CHANGELOG.md

@@ -5,6 +5,55 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.1.0] - 28.07.2023
+
+[Diff](https://github.com/elk-language/go-prompt/compare/v1.0.3...elk-language:go-prompt:v1.1.0)
+
+### Fixed
+- Fix cursor movement for text with grapheme clusters like 🇵🇱, 🙆🏿‍♂️
+
+### Added
+- Add `strings.GraphemeNumber`, a type that represents the amount of grapheme clusters in a string (or an offset of a grapheme cluster in a string)
+ - `type strings.GraphemeNumber int`
+- `func strings.RuneIndexNthGrapheme(text string, n strings.GraphemeNumber) strings.RuneNumber`
+- `func strings.RuneIndexNthColumn(text string, n strings.Width) strings.RuneNumber`
+- `func (*prompt.Document).GetCursorLeftPositionRunes(count strings.RuneNumber) strings.RuneNumber`
+- `func (*prompt.Document).GetCursorRightPositionRunes(count strings.RuneNumber) strings.RuneNumber`
+- `func (*prompt.Document).LastLineIndentLevel(indentSize int) int`
+- `func (*prompt.Document).LastLineIndentSpaces() int`
+- `func (*prompt.Buffer).DeleteRunes(count strings.RuneNumber, col strings.Width, row int) string`
+- `func (*prompt.Buffer).DeleteBeforeCursorRunes(count strings.RuneNumber, col strings.Width, row int) string`
+
+### Changed
+- Change signatures:
+ - `prompt.ExecuteOnEnterCallback`
+ - from `func(input string, indentSize int) (indent int, execute bool)`
+ - to `func(buffer *prompt.Buffer, indentSize int) (indent int, execute bool)`
+ - `(*prompt.Document).CursorPositionCol`
+ - from `func (*prompt.Document).CursorPositionCol() (col strings.RuneNumber)`
+ - to `func (*prompt.Document).CursorPositionCol() (col strings.Width)`
+ - `(*prompt.Document).GetCursorRightPosition`
+ - from `func (*prompt.Document).GetCursorRightPosition(count strings.RuneNumber) strings.RuneNumber`
+ - to `func (*prompt.Document).GetCursorRightPosition(count strings.Width) strings.RuneNumber`
+ - `(*prompt.Document).GetCursorLeftPosition`
+ - from `func (*prompt.Document).GetCursorLeftPosition(count strings.RuneNumber) strings.RuneNumber`
+ - to `func (*prompt.Document).GetCursorLeftPosition(count strings.Width) strings.RuneNumber`
+ - `(*prompt.Document).GetCursorUpPosition`
+ - from `func (*prompt.Document).GetCursorUpPosition(count int, preferredColumn strings.RuneNumber) strings.RuneNumber`
+ - to `func (*prompt.Document).GetCursorUpPosition(count int, preferredColumn strings.Width) strings.RuneNumber`
+ - `(*prompt.Document).GetCursorDownPosition`
+ - from `func (*prompt.Document).GetCursorDownPosition(count int, preferredColumn strings.RuneNumber) strings.RuneNumber`
+ - to `func (*prompt.Document).GetCursorDownPosition(count int, preferredColumn strings.Width) strings.RuneNumber`
+ - `(*prompt.Document).TranslateRowColToIndex`
+ - from `func (*prompt.Document).TranslateRowColToIndex(row int, column strings.RuneNumber) strings.RuneNumber`
+ - to `func (*prompt.Document).TranslateRowColToIndex(row int, column strings.Width) strings.RuneNumber`
+ - `(*prompt.Buffer).Delete`
+ - from `func (*Buffer).Delete(count istrings.RuneNumber, col istrings.Width, row int) string`
+ - to `func (*Buffer).Delete(count istrings.GraphemeNumber, col istrings.Width, row int) string`
+ - `(*prompt.Buffer).DeleteBeforeCursor`
+ - from `func (*Buffer).DeleteBeforeCursor(count istrings.RuneNumber, col istrings.Width, row int) string`
+ - to `func (*Buffer).DeleteBeforeCursor(count istrings.GraphemeNumber, col istrings.Width, row int) string`
+
 ## [1.0.3] - 25.07.2023
 
 [Diff](https://github.com/elk-language/go-prompt/compare/v1.0.2...elk-language:go-prompt:v1.0.3)

_example/automatic-indenter/main.go

@@ -18,7 +18,8 @@ func main() {
  p.Run()
 }
 
-func ExecuteOnEnter(input string, indentSize int) (int, bool) {
+func ExecuteOnEnter(buffer *prompt.Buffer, indentSize int) (int, bool) {
+ input := buffer.Text()
  lines := strings.SplitAfter(input, "\n")
  var spaces int
  if len(lines) > 0 {

_example/bang-executor/main.go

@@ -17,7 +17,8 @@ func main() {
  p.Run()
 }
 
-func ExecuteOnEnter(input string, indentSize int) (int, bool) {
+func ExecuteOnEnter(buffer *prompt.Buffer, indentSize int) (int, bool) {
+ input := buffer.Text()
  char, _ := utf8.DecodeLastRuneInString(input)
  return 0, char == '!'
 }

_example/simple-echo/cjk-cyrillic/main.go

@@ -4,20 +4,25 @@ import (
  "fmt"
 
  prompt "github.com/elk-language/go-prompt"
+ pstrings "github.com/elk-language/go-prompt/strings"
 )
 
 func executor(in string) {
  fmt.Println("Your input: " + in)
 }
 
-func completer(in prompt.Document) []prompt.Suggest {
+func completer(in prompt.Document) ([]prompt.Suggest, pstrings.RuneNumber, pstrings.RuneNumber) {
  s := []prompt.Suggest{
  {Text: "こんにちは", Description: "'こんにちは' means 'Hello' in Japanese"},
  {Text: "감사합니다", Description: "'안녕하세요' means 'Hello' in Korean."},
  {Text: "您好", Description: "'您好' means 'Hello' in Chinese."},
  {Text: "Добрый день", Description: "'Добрый день' means 'Hello' in Russian."},
  }
- return prompt.FilterHasPrefix(s, in.GetWordBeforeCursor(), true)
+ endIndex := in.CurrentRuneIndex()
+ w := in.GetWordBeforeCursor()
+ startIndex := endIndex - pstrings.RuneCountInString(w)
+
+ return prompt.FilterHasPrefix(s, w, true), startIndex, endIndex
 }
 
 func main() {

_example/simple-echo/main.go

@@ -4,16 +4,21 @@ import (
  "fmt"
 
  prompt "github.com/elk-language/go-prompt"
+ pstrings "github.com/elk-language/go-prompt/strings"
 )
 
-func completer(in prompt.Document) []prompt.Suggest {
+func completer(in prompt.Document) ([]prompt.Suggest, pstrings.RuneNumber, pstrings.RuneNumber) {
  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)
+ endIndex := in.CurrentRuneIndex()
+ w := in.GetWordBeforeCursor()
+ startIndex := endIndex - pstrings.RuneCountInString(w)
+
+ return prompt.FilterHasPrefix(s, w, true), startIndex, endIndex
 }
 
 func main() {
@@ -22,7 +27,6 @@ func main() {
  prompt.WithTitle("sql-prompt"),
  prompt.WithHistory([]string{"SELECT * FROM users;"}),
  prompt.WithPrefixTextColor(prompt.Yellow),
- prompt.WithPreviewSuggestionTextColor(prompt.Blue),
  prompt.WithSelectedSuggestionBGColor(prompt.LightGray),
  prompt.WithSuggestionBGColor(prompt.DarkGray),
  prompt.WithCompleter(completer),

buffer.go

@@ -5,6 +5,7 @@ import (
 
  "github.com/elk-language/go-prompt/debug"
  istrings "github.com/elk-language/go-prompt/strings"
+ "golang.org/x/exp/utf8string"
 )
 
 // Buffer emulates the console buffer.
@@ -14,7 +15,7 @@ type Buffer struct {
  startLine int // Line number of the first visible line in the terminal (0-indexed)
  cursorPosition istrings.RuneNumber
  cacheDocument *Document
- preferredColumn istrings.RuneNumber // Remember the original column for the next up/down movement.
+ preferredColumn istrings.Width // Remember the original column for the next up/down movement.
  lastKeyStroke Key
 }
 
@@ -187,22 +188,59 @@ func (b *Buffer) CursorDown(count int, columns istrings.Width, rows int) bool {
  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, columns istrings.Width, rows int) (deleted string) {
+// DeleteBeforeCursor delete specified number of graphemes before the cursor and returns the deleted text.
+func (b *Buffer) DeleteBeforeCursor(count istrings.GraphemeNumber, columns istrings.Width, rows int) string {
  debug.Assert(count >= 0, "count should be positive")
+ if b.cursorPosition < 0 {
+ return ""
+ }
+
+ var deleted string
+
+ textUtf8 := utf8string.NewString(b.Text())
+ textBeforeCursor := textUtf8.Slice(0, int(b.cursorPosition))
+ graphemeLength := istrings.GraphemeCount(textBeforeCursor)
+
+ start := istrings.RuneIndexNthGrapheme(textBeforeCursor, graphemeLength-count)
+ if start < 0 {
+ start = 0
+ }
+ deleted = textUtf8.Slice(int(start), int(b.cursorPosition))
+ b.setDocument(
+ &Document{
+ Text: textUtf8.Slice(0, int(start)) + textUtf8.Slice(int(b.cursorPosition), textUtf8.RuneCount()),
+ cursorPosition: b.cursorPosition - istrings.RuneCountInString(deleted),
+ },
+ columns,
+ rows,
+ )
+
+ b.recalculateStartLine(columns, rows)
+ b.updatePreferredColumn()
+ return deleted
+}
+
+// Deletes the specified number of runes before the cursor and returns the deleted text.
+func (b *Buffer) DeleteBeforeCursorRunes(count istrings.RuneNumber, columns istrings.Width, rows int) (deleted string) {
+ debug.Assert(count >= 0, "count should be positive")
+ if b.cursorPosition <= 0 {
+ return ""
+ }
  r := []rune(b.Text())
 
- if b.cursorPosition > 0 {
-  start := b.cursorPosition - count
- if start < 0 {
-  start = 0
-  }
-  deleted = string(r[start:b.cursorPosition])
- b.setDocument(&Document{
+ start := b.cursorPosition - count
+ if start < 0 {
+ start = 0
+ }
+ deleted = string(r[start:b.cursorPosition])
+ b.setDocument(
+ &Document{
  Text: string(r[:start]) + string(r[b.cursorPosition:]),
  cursorPosition: b.cursorPosition - istrings.RuneNumber(len([]rune(deleted))),
- }, columns, rows)
- }
+ },
+ columns,
+ rows,
+ )
  b.recalculateStartLine(columns, rows)
  b.updatePreferredColumn()
  return
@@ -217,8 +255,30 @@ func (b *Buffer) NewLine(columns istrings.Width, rows int, copyMargin bool) {
  }
 }
 
-// Delete specified number of characters and Return the deleted text.
-func (b *Buffer) Delete(count istrings.RuneNumber, col istrings.Width, row int) string {
+// Deletes the specified number of graphemes and returns the deleted text.
+func (b *Buffer) Delete(count istrings.GraphemeNumber, col istrings.Width, row int) string {
+ textUtf8 := utf8string.NewString(b.Text())
+ if b.cursorPosition >= istrings.RuneCountInString(b.Text()) {
+ return ""
+ }
+
+ textAfterCursor := b.Document().TextAfterCursor()
+ textAfterCursorUtf8 := utf8string.NewString(textAfterCursor)
+
+ deletedRunes := textAfterCursorUtf8.Slice(0, int(istrings.RuneIndexNthGrapheme(textAfterCursor, count)))
+
+ b.setText(
+ textUtf8.Slice(0, int(b.cursorPosition))+textUtf8.Slice(int(b.cursorPosition)+int(istrings.RuneCountInString(deletedRunes)), textUtf8.RuneCount()),
+ col,
+ row,
+ )
+
+ deleted := string(deletedRunes)
+ return deleted
+}
+
+// Deletes the specified number of runes and returns the deleted text.
+func (b *Buffer) DeleteRunes(count istrings.RuneNumber, col istrings.Width, row int) string {
  r := []rune(b.Text())
  if b.cursorPosition < istrings.RuneNumber(len(r)) {
  textAfterCursor := b.Document().TextAfterCursor()

constructor.go

@@ -286,7 +286,7 @@ func WithExitChecker(fn ExitChecker) Option {
  }
 }
 
-func DefaultExecuteOnEnterCallback(input string, indentSize int) (int, bool) {
+func DefaultExecuteOnEnterCallback(buffer *Buffer, indentSize int) (int, bool) {
  return 0, true
 }
 

document.go

@@ -62,6 +62,32 @@ func (d *Document) CurrentRuneIndex() istrings.RuneNumber {
  return d.cursorPosition
 }
 
+// Returns the amount of spaces that the last line of input
+// is indented with.
+func (d *Document) LastLineIndentSpaces() int {
+ input := d.Text
+ lastNewline := strings.LastIndexByte(input, '\n')
+ var spaces int
+ for i := lastNewline + 1; i < len(input); i++ {
+ b := input[i]
+ if b != ' ' {
+ break
+ }
+
+ spaces++
+ }
+
+ return spaces
+}
+
+// Returns the indentation level of the last line of input.
+func (d *Document) LastLineIndentLevel(indentSize int) int {
+ if indentSize == 0 {
+ return 0
+ }
+ return d.LastLineIndentSpaces() / indentSize
+}
+
 // TextBeforeCursor returns the text before the cursor.
 func (d *Document) TextBeforeCursor() string {
  r := []rune(d.Text)
@@ -354,10 +380,11 @@ func (d *Document) TextEndPositionRow() (row istrings.RuneNumber) {
 }
 
 // CursorPositionCol returns the current column. (0-based.)
-func (d *Document) CursorPositionCol() (col istrings.RuneNumber) {
- _, index := d.findLineStartIndex(d.cursorPosition)
- col = d.cursorPosition - index
- return
+func (d *Document) CursorPositionCol() (col istrings.Width) {
+ _, lineStartIndex := d.findLineStartIndex(d.cursorPosition)
+
+ text := utf8string.NewString(d.Text).Slice(int(lineStartIndex), int(d.cursorPosition))
+ return istrings.GetWidth(text)
 }
 
 // Returns the amount of runes that the cursors should be moved by.
@@ -420,18 +447,7 @@ func (d *Document) GetCursorRightPosition(count istrings.GraphemeNumber) istring
  return 0
  }
 
- g := uniseg.NewGraphemes(text)
- var currentGraphemeIndex istrings.GraphemeNumber
- var currentPosition istrings.RuneNumber
-
- for g.Next() {
- if currentGraphemeIndex >= count {
- break
- }
- currentPosition += istrings.RuneNumber(len(g.Runes()))
- currentGraphemeIndex++
- }
- return currentPosition
+ return istrings.RuneIndexNthGrapheme(text, count)
 }
 
 // Returns the amount of runes that the cursors should be moved by.
@@ -466,8 +482,8 @@ func (d *Document) GetEndOfTextPosition(columns istrings.Width) Position {
 
 // GetCursorUpPosition return the relative cursor position (character index) where we would be
 // if the user pressed the arrow-up button.
-func (d *Document) GetCursorUpPosition(count int, preferredColumn istrings.RuneNumber) istrings.RuneNumber {
- var col istrings.RuneNumber
+func (d *Document) GetCursorUpPosition(count int, preferredColumn istrings.Width) istrings.RuneNumber {
+ var col istrings.Width
  if preferredColumn == -1 { // -1 means nil
  col = d.CursorPositionCol()
  } else {
@@ -483,8 +499,8 @@ func (d *Document) GetCursorUpPosition(count int, preferredColumn istrings.RuneN
 
 // GetCursorDownPosition return the relative cursor position (character index) where we would be if the
 // user pressed the arrow-down button.
-func (d *Document) GetCursorDownPosition(count int, preferredColumn istrings.RuneNumber) istrings.RuneNumber {
- var col istrings.RuneNumber
+func (d *Document) GetCursorDownPosition(count int, preferredColumn istrings.Width) istrings.RuneNumber {
+ var col istrings.Width
  if preferredColumn == -1 { // -1 means nil
  col = d.CursorPositionCol()
  } else {
@@ -516,31 +532,24 @@ func (d *Document) TranslateIndexToPosition(index istrings.RuneNumber) (int, int
 
 // TranslateRowColToIndex given a (row, col), return the corresponding index.
 // (Row and col params are 0-based.)
-func (d *Document) TranslateRowColToIndex(row int, column istrings.RuneNumber) (index istrings.RuneNumber) {
+func (d *Document) TranslateRowColToIndex(row int, column istrings.Width) (index istrings.RuneNumber) {
  indices := d.lineStartIndices()
  if row < 0 {
  row = 0
  } else if row > len(indices) {
  row = len(indices) - 1
  }
  index = indices[row]
- line := []rune(d.Lines()[row])
-
- // python) result += max(0, min(col, len(line)))
- if column > 0 || len(line) > 0 {
- if column > istrings.RuneNumber(len(line)) {
- index += istrings.RuneNumber(len(line))
- } else {
- index += istrings.RuneNumber(column)
- }
- }
+ line := d.Lines()[row]
+
+ index += istrings.RuneIndexNthColumn(line, column)
 
- text := []rune(d.Text)
+ runeLength := istrings.RuneCountInString(d.Text)
  // Keep in range. (len(self.text) is included, because the cursor can be
  // right after the end of the text as well.)
  // python) result = max(0, min(result, len(self.text)))
- if index > istrings.RuneNumber(len(text)) {
- index = istrings.RuneNumber(len(text))
+ if index > runeLength {
+ index = runeLength
  }
  if index < 0 {
  index = 0