Fix horizontal cursor movements when there are grapheme clusters

_example/http-prompt/main.go

@@ -164,7 +164,7 @@ func completer(in prompt.Document) ([]prompt.Suggest, istrings.RuneNumber, istri
  if w == "" {
  return []prompt.Suggest{}, 0, 0
  }
- startIndex := endIndex - istrings.RuneCount(w)
+ startIndex := endIndex - istrings.RuneCountInString(w)
  return prompt.FilterHasPrefix(suggestions, w, true), startIndex, endIndex
 }
 

_example/live-prefix/main.go

@@ -21,7 +21,7 @@ func executor(in string) {
 func completer(in prompt.Document) ([]prompt.Suggest, istrings.RuneNumber, istrings.RuneNumber) {
  endIndex := in.CurrentRuneIndex()
  w := in.GetWordBeforeCursor()
- startIndex := endIndex - istrings.RuneCount(w)
+ startIndex := endIndex - istrings.RuneCountInString(w)
 
  s := []prompt.Suggest{
  {Text: "users", Description: "Store the username and age"},

buffer.go

@@ -69,13 +69,13 @@ func (b *Buffer) insertText(text string, columns istrings.Width, rows int, overw
  if overwrite {
  overwritten := string(currentTextRunes[cursor:])
  if len(overwritten) >= int(cursor)+len(text) {
- overwritten = string(currentTextRunes[cursor : cursor+istrings.RuneCount(text)])
+ overwritten = string(currentTextRunes[cursor : cursor+istrings.RuneCountInString(text)])
  }
  if i := strings.IndexAny(overwritten, "\n"); i != -1 {
  overwritten = overwritten[:i]
  }
  b.setText(
- string(currentTextRunes[:cursor])+text+string(currentTextRunes[cursor+istrings.RuneCount(overwritten):]),
+ string(currentTextRunes[:cursor])+text+string(currentTextRunes[cursor+istrings.RuneCountInString(overwritten):]),
  columns,
  rows,
  )
@@ -88,7 +88,7 @@ func (b *Buffer) insertText(text string, columns istrings.Width, rows int, overw
  }
 
  if moveCursor {
- b.cursorPosition += istrings.RuneCount(text)
+ b.cursorPosition += istrings.RuneCountInString(text)
  b.recalculateStartLine(columns, rows)
  b.updatePreferredColumn()
  }
@@ -118,7 +118,7 @@ func (b *Buffer) recalculateStartLine(columns istrings.Width, rows int) bool {
 // (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, col istrings.Width, row int) {
- debug.Assert(b.cursorPosition <= istrings.RuneCount(text), "length of input should be shorter than cursor position")
+ debug.Assert(b.cursorPosition <= istrings.RuneCountInString(text), "length of input should be shorter than cursor position")
  b.workingLines[b.workingIndex] = text
  b.recalculateStartLine(col, row)
  b.resetPreferredColumn()
@@ -141,20 +141,32 @@ func (b *Buffer) setDocument(d *Document, columns istrings.Width, rows int) {
  b.resetPreferredColumn()
 }
 
-// Move to the left on the current line.
+// Move to the left on the current line by the given amount of graphemes.
 // 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
- b.updatePreferredColumn()
- return b.recalculateStartLine(columns, rows)
+func (b *Buffer) CursorLeft(count istrings.GraphemeNumber, columns istrings.Width, rows int) bool {
+ return b.cursorHorizontalMove(b.Document().GetCursorLeftPosition(count), columns, rows)
+}
+
+// Move to the left on the current line by the given amount of runes.
+// Returns true when the view should be rerendered.
+func (b *Buffer) CursorLeftRunes(count istrings.RuneNumber, columns istrings.Width, rows int) bool {
+ return b.cursorHorizontalMove(b.Document().GetCursorLeftPositionRunes(count), columns, rows)
 }
 
-// Move to the right on the current line.
+// Move to the right on the current line by the given amount of graphemes.
 // 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
+func (b *Buffer) CursorRight(count istrings.GraphemeNumber, columns istrings.Width, rows int) bool {
+ return b.cursorHorizontalMove(b.Document().GetCursorRightPosition(count), columns, rows)
+}
+
+// Move to the right on the current line by the given amount of runes.
+// Returns true when the view should be rerendered.
+func (b *Buffer) CursorRightRunes(count istrings.RuneNumber, columns istrings.Width, rows int) bool {
+ return b.cursorHorizontalMove(b.Document().GetCursorRightPositionRunes(count), columns, rows)
+}
+
+func (b *Buffer) cursorHorizontalMove(count istrings.RuneNumber, columns istrings.Width, rows int) bool {
+ b.cursorPosition += count
  b.updatePreferredColumn()
  return b.recalculateStartLine(columns, rows)
 }

buffer_test.go

@@ -25,8 +25,8 @@ func TestBuffer_InsertText(t *testing.T) {
  t.Errorf("Text should be %#v, got %#v", "some_text", b.Text())
  }
 
- if b.cursorPosition != istrings.RuneCount("some_text") {
- t.Errorf("cursorPosition should be %#v, got %#v", istrings.RuneCount("some_text"), b.cursorPosition)
+ if b.cursorPosition != istrings.RuneCountInString("some_text") {
+ t.Errorf("cursorPosition should be %#v, got %#v", istrings.RuneCountInString("some_text"), b.cursorPosition)
  }
 }
 
@@ -38,8 +38,8 @@ func TestBuffer_InsertText_Overwrite(t *testing.T) {
  t.Errorf("Text should be %#v, got %#v", "ABC", b.Text())
  }
 
- if b.cursorPosition != istrings.RuneCount("ABC") {
- t.Errorf("cursorPosition should be %#v, got %#v", istrings.RuneCount("ABC"), b.cursorPosition)
+ if b.cursorPosition != istrings.RuneCountInString("ABC") {
+ t.Errorf("cursorPosition should be %#v, got %#v", istrings.RuneCountInString("ABC"), b.cursorPosition)
  }
 
  b.CursorLeft(1, DefColCount, DefRowCount)
@@ -87,8 +87,8 @@ func TestBuffer_CursorMovement(t *testing.T) {
  if b.Text() != "some_teAxt" {
  t.Errorf("Text should be %#v, got %#v", "some_teAxt", b.Text())
  }
- if b.cursorPosition != istrings.RuneCount("some_teA") {
- t.Errorf("Text should be %#v, got %#v", istrings.RuneCount("some_teA"), b.cursorPosition)
+ if b.cursorPosition != istrings.RuneCountInString("some_teA") {
+ t.Errorf("Text should be %#v, got %#v", istrings.RuneCountInString("some_teA"), b.cursorPosition)
  }
 
  // Moving over left character counts.
@@ -97,8 +97,8 @@ func TestBuffer_CursorMovement(t *testing.T) {
  if b.Text() != "Asome_teAxt" {
  t.Errorf("Text should be %#v, got %#v", "some_teAxt", b.Text())
  }
- if b.cursorPosition != istrings.RuneCount("A") {
- t.Errorf("Text should be %#v, got %#v", istrings.RuneCount("some_teA"), b.cursorPosition)
+ if b.cursorPosition != istrings.RuneCountInString("A") {
+ t.Errorf("Text should be %#v, got %#v", istrings.RuneCountInString("some_teA"), b.cursorPosition)
  }
 
  // TODO: Going right already at right end.
@@ -148,17 +148,17 @@ func TestBuffer_CursorDown(t *testing.T) {
 
  // Normally going down
  b.CursorDown(1, DefColCount, DefRowCount)
- if b.Document().cursorPosition != istrings.RuneCount("line1\nlin") {
- t.Errorf("Should be %#v, got %#v", istrings.RuneCount("line1\nlin"), b.Document().cursorPosition)
+ if b.Document().cursorPosition != istrings.RuneCountInString("line1\nlin") {
+ t.Errorf("Should be %#v, got %#v", istrings.RuneCountInString("line1\nlin"), b.Document().cursorPosition)
  }
 
  // Going down to a line that's storter.
  b = NewBuffer()
  b.InsertTextMoveCursor("long line1\na\nb", DefColCount, DefRowCount, false)
  b.cursorPosition = 3
  b.CursorDown(1, DefColCount, DefRowCount)
- if b.Document().cursorPosition != istrings.RuneCount("long line1\na") {
- t.Errorf("Should be %#v, got %#v", istrings.RuneCount("long line1\na"), b.Document().cursorPosition)
+ if b.Document().cursorPosition != istrings.RuneCountInString("long line1\na") {
+ t.Errorf("Should be %#v, got %#v", istrings.RuneCountInString("long line1\na"), b.Document().cursorPosition)
  }
 }
 
@@ -174,8 +174,8 @@ func TestBuffer_DeleteBeforeCursor(t *testing.T) {
  if deleted != "e" {
  t.Errorf("Should be %#v, got %#v", deleted, "e")
  }
- if b.cursorPosition != istrings.RuneCount("some_t") {
- t.Errorf("Should be %#v, got %#v", istrings.RuneCount("some_t"), b.cursorPosition)
+ if b.cursorPosition != istrings.RuneCountInString("some_t") {
+ t.Errorf("Should be %#v, got %#v", istrings.RuneCountInString("some_t"), b.cursorPosition)
  }
 
  // Delete over the characters length before cursor.

document.go

@@ -7,6 +7,7 @@ import (
 
  "github.com/elk-language/go-prompt/bisect"
  istrings "github.com/elk-language/go-prompt/strings"
+ "github.com/rivo/uniseg"
  "golang.org/x/exp/utf8string"
 )
 
@@ -142,7 +143,7 @@ func (d *Document) FindStartOfPreviousWord() istrings.ByteNumber {
 // of the text before the cursor until the start of the previous word.
 func (d *Document) FindRuneNumberUntilStartOfPreviousWord() istrings.RuneNumber {
  x := d.TextBeforeCursor()
- return istrings.RuneCount(x[d.FindStartOfPreviousWordWithSpace():])
+ return istrings.RuneCountInString(x[d.FindStartOfPreviousWordWithSpace():])
 }
 
 // FindStartOfPreviousWordWithSpace is almost the same as FindStartOfPreviousWord.
@@ -344,7 +345,7 @@ func (d *Document) CursorPositionRow() (row istrings.RuneNumber) {
 
 // TextEndPositionRow returns the row of the end of the current text. (0-based.)
 func (d *Document) TextEndPositionRow() (row istrings.RuneNumber) {
- textLength := istrings.RuneCount(d.Text)
+ textLength := istrings.RuneCountInString(d.Text)
  if textLength == 0 {
  return 0
  }
@@ -359,11 +360,41 @@ func (d *Document) CursorPositionCol() (col istrings.RuneNumber) {
  return
 }
 
-// GetCursorLeftPosition returns the relative position for cursor left.
-func (d *Document) GetCursorLeftPosition(count istrings.RuneNumber) istrings.RuneNumber {
+// Returns the amount of runes that the cursors should be moved by.
+// The `count` argument tells this function by how many graphemes (visible characters)
+// the cursor should be moved (to the left).
+func (d *Document) GetCursorLeftPosition(count istrings.GraphemeNumber) istrings.RuneNumber {
  if count < 0 {
  return d.GetCursorRightPosition(-count)
  }
+ if d.cursorPosition == 0 {
+ return 0
+ }
+ text := d.TextBeforeCursor()
+ g := uniseg.NewGraphemes(text)
+ graphemeLength := istrings.GraphemeCount(text)
+ var currentGraphemeIndex istrings.GraphemeNumber
+ var currentPosition istrings.RuneNumber
+
+ for g.Next() {
+ if currentGraphemeIndex >= graphemeLength-count {
+ break
+ }
+ currentPosition += istrings.RuneNumber(len(g.Runes()))
+ currentGraphemeIndex++
+ }
+
+ result := d.cursorPosition - currentPosition
+ return -result
+}
+
+// Returns the amount of runes that the cursors should be moved by.
+// The `count` argument tells this function by how many runes
+// the cursor should be moved (to the left).
+func (d *Document) GetCursorLeftPositionRunes(count istrings.RuneNumber) istrings.RuneNumber {
+ if count < 0 {
+ return d.GetCursorRightPositionRunes(-count)
+ }
  runeSlice := []rune(d.Text)
  var counter istrings.RuneNumber
  targetPosition := d.cursorPosition - count
@@ -377,11 +408,39 @@ func (d *Document) GetCursorLeftPosition(count istrings.RuneNumber) istrings.Run
  return counter
 }
 
-// GetCursorRightPosition returns relative position for cursor right.
-func (d *Document) GetCursorRightPosition(count istrings.RuneNumber) istrings.RuneNumber {
+// Returns the amount of runes that the cursors should be moved by.
+// The `count` argument tells this function by how many graphemes (visible characters)
+// the cursor should be moved (to the right).
+func (d *Document) GetCursorRightPosition(count istrings.GraphemeNumber) istrings.RuneNumber {
  if count < 0 {
  return d.GetCursorLeftPosition(-count)
  }
+ text := d.TextAfterCursor()
+ if len(text) == 0 {
+ 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
+}
+
+// Returns the amount of runes that the cursors should be moved by.
+// The `count` argument tells this function by how many runes
+// the cursor should be moved (to the right).
+func (d *Document) GetCursorRightPositionRunes(count istrings.RuneNumber) istrings.RuneNumber {
+ if count < 0 {
+ return d.GetCursorLeftPositionRunes(-count)
+ }
  runeSlice := []rune(d.Text)
  var counter istrings.RuneNumber
  targetPosition := d.cursorPosition + count
@@ -496,12 +555,12 @@ func (d *Document) OnLastLine() bool {
 
 // GetEndOfLinePosition returns relative position for the end of this line.
 func (d *Document) GetEndOfLinePosition() istrings.RuneNumber {
- return istrings.RuneCount(d.CurrentLineAfterCursor())
+ return istrings.RuneCountInString(d.CurrentLineAfterCursor())
 }
 
 // GetStartOfLinePosition returns relative position for the start of this line.
 func (d *Document) GetStartOfLinePosition() istrings.RuneNumber {
- return istrings.RuneCount(d.CurrentLineBeforeCursor())
+ return istrings.RuneCountInString(d.CurrentLineBeforeCursor())
 }
 
 // GetStartOfLinePosition returns relative position for the start of this line.
@@ -521,7 +580,7 @@ func (d *Document) FindStartOfFirstWordOfLine() istrings.RuneNumber {
  }
 
  if counter == 0 {
- return istrings.RuneCount(line)
+ return istrings.RuneCountInString(line)
  }
 
  return counter