Add more formatting options for tokens

CHANGELOG.md

@@ -5,8 +5,36 @@ 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).
 
+## [1.0.2] - 25.07.2023
 
-## [1.0.0]
+[Diff](https://github.com/elk-language/go-prompt/compare/v1.0.1...elk-language:go-prompt:v1.0.2)
+
+### Added
+
+- `prompt.Token` has new methods:
+ - `BackgroundColor() prompt.Color` - define the background color for the token
+ - `DisplayAttributes() []prompt.DisplayAttribute` - define the font eg. bold, italic, underline
+- `prompt.NewSimpleToken` has new options:
+ - `prompt.SimpleTokenWithColor(c Color) SimpleTokenOption`
+ - `prompt.SimpleTokenWithBackgroundColor(c Color) SimpleTokenOption`
+ - `prompt.SimpleTokenWithDisplayAttributes(attrs ...DisplayAttribute) SimpleTokenOption`
+- `prompt.Writer` has new methods:
+ - `prompt.SetDisplayAttributes(fg, bg Color, attrs ...DisplayAttribute)`
+
+### Changed
+
+- change the signature of `prompt.NewSimpleToken` from `func NewSimpleToken(color Color, firstIndex, lastIndex istrings.ByteNumber) *SimpleToken` to `func NewSimpleToken(firstIndex, lastIndex istrings.ByteNumber, opts ...SimpleTokenOption) *SimpleToken`
+
+## [1.0.1] - 25.07.2023
+
+[Diff](https://github.com/elk-language/go-prompt/compare/v1.0.0...elk-language:go-prompt:v1.0.1)
+
+### Added
+
+- `prompt.Token` has a new method `FirstByteIndex() strings.ByteNumber`
+
+
+## [1.0.0] - 25.07.2023
 
 [Diff](https://github.com/elk-language/go-prompt/compare/v0.2.6...elk-language:go-prompt:v1.0.0)
 

_example/even-lexer/main.go

@@ -32,7 +32,11 @@ func charLexer(line string) []prompt.Token {
  color = prompt.White
  }
  lastByteIndex := strings.ByteNumber(i + utf8.RuneLen(value) - 1)
- element := prompt.NewSimpleToken(color, strings.ByteNumber(i), lastByteIndex)
+ element := prompt.NewSimpleToken(
+ strings.ByteNumber(i),
+ lastByteIndex,
+ prompt.SimpleTokenWithColor(color),
+ )
 
  elements = append(elements, element)
  }
@@ -67,7 +71,11 @@ func wordLexer(line string) []prompt.Token {
  color = prompt.White
  }
 
- element := prompt.NewSimpleToken(color, firstByte, currentByte-1)
+ element := prompt.NewSimpleToken(
+ firstByte,
+ currentByte-1,
+ prompt.SimpleTokenWithColor(color),
+ )
  elements = append(elements, element)
  wordIndex++
  firstCharSeen = false
@@ -84,11 +92,14 @@ func wordLexer(line string) []prompt.Token {
  } else {
  color = prompt.White
  }
- element := prompt.NewSimpleToken(color, firstByte, currentByte+strings.ByteNumber(utf8.RuneLen(lastChar))-1)
+ element := prompt.NewSimpleToken(
+ firstByte,
+ currentByte+strings.ByteNumber(utf8.RuneLen(lastChar))-1,
+ prompt.SimpleTokenWithColor(color),
+ )
  elements = append(elements, element)
  }
 
- prompt.Log("tokens: %#v", elements)
  return elements
 }
 

buffer.go

@@ -9,19 +9,28 @@ import (
 
 // Buffer emulates the console buffer.
 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
+ 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
+ preferredColumn istrings.RuneNumber // Remember the original column for the next up/down movement.
+ lastKeyStroke Key
 }
 
 // Text returns string of the current line.
 func (b *Buffer) Text() string {
  return b.workingLines[b.workingIndex]
 }
 
+func (b *Buffer) resetPreferredColumn() {
+ b.preferredColumn = -1
+}
+
+func (b *Buffer) updatePreferredColumn() {
+ b.preferredColumn = b.Document().CursorPositionCol()
+}
+
 // Document method to return document instance from the current text and cursor position.
 func (b *Buffer) Document() (d *Document) {
  if b.cacheDocument == nil ||
@@ -80,16 +89,17 @@ func (b *Buffer) insertText(text string, columns istrings.Width, rows int, overw
 
  if moveCursor {
  b.cursorPosition += istrings.RuneCount(text)
- b.RecalculateStartLine(columns, rows)
+ b.recalculateStartLine(columns, rows)
+ b.updatePreferredColumn()
  }
 }
 
-func (b *Buffer) ResetStartLine() {
+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 {
+func (b *Buffer) recalculateStartLine(columns istrings.Width, rows int) bool {
  origStartLine := b.startLine
  pos := b.DisplayCursorPosition(columns)
  if pos.Y > b.startLine+rows-1 {
@@ -110,7 +120,8 @@ func (b *Buffer) RecalculateStartLine(columns istrings.Width, rows int) bool {
 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)
+ b.recalculateStartLine(col, row)
+ b.resetPreferredColumn()
 }
 
 // Set cursor position. Return whether it changed.
@@ -126,41 +137,42 @@ 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, columns, rows)
- b.RecalculateStartLine(columns, rows)
+ b.recalculateStartLine(columns, rows)
+ b.resetPreferredColumn()
 }
 
 // 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)
+ b.updatePreferredColumn()
+ return b.recalculateStartLine(columns, rows)
 }
 
 // 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)
+ b.updatePreferredColumn()
+ return b.recalculateStartLine(columns, rows)
 }
 
 // CursorUp move cursor to the previous line.
 // (for multi-line edit).
 // 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)
+ b.cursorPosition += b.Document().GetCursorUpPosition(count, b.preferredColumn)
+ return b.recalculateStartLine(columns, rows)
 }
 
 // CursorDown move cursor to the next line.
 // (for multi-line edit).
 // 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)
+ b.cursorPosition += b.Document().GetCursorDownPosition(count, b.preferredColumn)
+ return b.recalculateStartLine(columns, rows)
 }
 
 // DeleteBeforeCursor delete specified number of characters before cursor and return the deleted text.
@@ -179,7 +191,8 @@ func (b *Buffer) DeleteBeforeCursor(count istrings.RuneNumber, columns istrings.
  cursorPosition: b.cursorPosition - istrings.RuneNumber(len([]rune(deleted))),
  }, columns, rows)
  }
- b.RecalculateStartLine(columns, rows)
+ b.recalculateStartLine(columns, rows)
+ b.updatePreferredColumn()
  return
 }
 
@@ -206,7 +219,6 @@ func (b *Buffer) Delete(count istrings.RuneNumber, col istrings.Width, row int)
  )
 
  deleted := string(deletedRunes)
- b.RecalculateStartLine(col, row)
  return deleted
  }
 
@@ -243,9 +255,10 @@ func (b *Buffer) SwapCharactersBeforeCursor(col istrings.Width, row int) {
 // NewBuffer is constructor of Buffer struct.
 func NewBuffer() (b *Buffer) {
  b = &Buffer{
- workingLines: []string{""},
- workingIndex: 0,
- startLine: 0,
+ workingLines: []string{""},
+ workingIndex: 0,
+ startLine: 0,
+ preferredColumn: -1,
  }
  return
 }

lexer.go

@@ -15,32 +15,71 @@ type Lexer interface {
 
 // Token is a single unit of text returned by a Lexer.
 type Token interface {
- Color() Color // Color of the token
+ Color() Color // Color of the token's text
+ BackgroundColor() Color
+ DisplayAttributes() []DisplayAttribute
  FirstByteIndex() istrings.ByteNumber // Index of the last byte of this token
  LastByteIndex() istrings.ByteNumber // Index of the last byte of this token
 }
 
 // SimpleToken as the default implementation of Token.
 type SimpleToken struct {
- color Color
- lastByteIndex istrings.ByteNumber
- firstByteIndex istrings.ByteNumber
+ color Color
+ backgroundColor Color
+ displayAttributes []DisplayAttribute
+ lastByteIndex istrings.ByteNumber
+ firstByteIndex istrings.ByteNumber
+}
+
+type SimpleTokenOption func(*SimpleToken)
+
+func SimpleTokenWithColor(c Color) SimpleTokenOption {
+ return func(t *SimpleToken) {
+ t.color = c
+ }
+}
+
+func SimpleTokenWithBackgroundColor(c Color) SimpleTokenOption {
+ return func(t *SimpleToken) {
+ t.backgroundColor = c
+ }
+}
+
+func SimpleTokenWithDisplayAttributes(attrs ...DisplayAttribute) SimpleTokenOption {
+ return func(t *SimpleToken) {
+ t.displayAttributes = attrs
+ }
 }
 
 // Create a new SimpleToken.
-func NewSimpleToken(color Color, firstIndex, lastIndex istrings.ByteNumber) *SimpleToken {
- return &SimpleToken{
- color: color,
+func NewSimpleToken(firstIndex, lastIndex istrings.ByteNumber, opts ...SimpleTokenOption) *SimpleToken {
+ t := &SimpleToken{
  firstByteIndex: firstIndex,
  lastByteIndex: lastIndex,
  }
+
+ for _, opt := range opts {
+ opt(t)
+ }
+
+ return t
 }
 
-// Retrieve the color of this token.
+// Retrieve the text color of this token.
 func (t *SimpleToken) Color() Color {
  return t.color
 }
 
+// Retrieve the background color of this token.
+func (t *SimpleToken) BackgroundColor() Color {
+ return t.backgroundColor
+}
+
+// Retrieve the display attributes of this token eg. bold, underline.
+func (t *SimpleToken) DisplayAttributes() []DisplayAttribute {
+ return t.displayAttributes
+}
+
 // The index of the last byte of the lexeme.
 func (t *SimpleToken) LastByteIndex() istrings.ByteNumber {
  return t.lastByteIndex

lexer_test.go

@@ -70,7 +70,7 @@ func TestEagerLexerNext(t *testing.T) {
 func charLex(s string) []Token {
  var result []Token
  for i := range s {
- result = append(result, NewSimpleToken(0, istrings.ByteNumber(i), istrings.ByteNumber(i)))
+ result = append(result, NewSimpleToken(istrings.ByteNumber(i), istrings.ByteNumber(i)))
  }
 
  return result

prompt.go

@@ -125,8 +125,8 @@ func (p *Prompt) Run() {
  }
  case w := <-winSizeCh:
  p.renderer.UpdateWinSize(w)
- p.Buffer.ResetStartLine()
- p.Buffer.RecalculateStartLine(p.renderer.UserInputColumns(), int(p.renderer.row))
+ p.Buffer.resetStartLine()
+ p.Buffer.recalculateStartLine(p.renderer.UserInputColumns(), int(p.renderer.row))
  p.renderer.Render(p.Buffer, p.completion, p.lexer)
  case code := <-exitCh:
  p.renderer.BreakLine(p.Buffer, p.lexer)