FEATURES.md

@@ -133,8 +133,8 @@
 - [ ] `U` - Undo all changes on line
 
 ### Other Normal Mode
-- [ ] `r{char}` - Replace character
-- [ ] `R` - Replace mode
+- [x] `r{char}` - Replace character
+- [x] `R` - Replace mode
 - [ ] `~` - Swap case of character
 - [ ] `ctrl+a` - Increment number
 - [ ] `ctrl+x` - Decrement number

README.md

@@ -64,6 +64,18 @@ While the undo tree method that vim uses is powerful, I rarely find myself using
 approach is more natural to "non-vim" users and much simpler to implement. Implementing a feature similar
 to Vims undo tree would many times longer than a simple stack.
 
+#### Vim-like Replace vs. Custom Replace
+
+The way that vim's replace mode is implemented is quite complex, keeping track of the previous
+line backspace can only delete newly replaced characters. This is a complex feature, one that 
+I rarely use, and even find a bit un-intuitive. Implementing replace mode in a way where all 
+actions function the same as insert mode (other than the actual character typing) allows for 
+a much simpler implementation, as well as a more intuitive user experience.
+
+Replace mode implements and replaces (no pun intended) the last inserted keys of insert mode. Due to
+the infrequent use of replace mode, and the '.' action for insert mode, this felt like a natural 
+trade off.
+
 ---
 
 ## TODO List

internal/action/replace.go

@@ -0,0 +1,129 @@
+package action
+
+import (
+	"strings"
+
+	"git.gophernest.net/azpect/TextEditor/internal/core"
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+type ReplaceChar struct {
+	Char  string
+	Count int
+}
+
+func (m ReplaceChar) WithChar(char string) Motion {
+	m.Char = char
+	return m
+}
+
+func (m ReplaceChar) Type() core.MotionType {
+	return core.CharwiseInclusive
+}
+
+// WithCount sets the count (required by Repeatable interface)
+func (m ReplaceChar) WithCount(n int) Action {
+	m.Count = n
+	return m
+}
+
+func (a ReplaceChar) Execute(m Model) tea.Cmd {
+	win := m.ActiveWindow()
+	buf := m.ActiveBuffer()
+
+	if buf.UndoStack != nil && !buf.UndoStack.Recording() {
+		buf.UndoStack.BeginBlock(win.Cursor)
+	}
+
+	pos := win.Cursor.Col
+	line := buf.Line(win.Cursor.Line)
+	for i := 0; i < a.Count && pos < len(line); i++ {
+		line = line[:pos] + a.Char + line[pos+1:]
+		buf.SetLine(win.Cursor.Line, line)
+		pos++
+	}
+
+	win.SetCursorCol(pos - 1)
+	m.SetMode(core.NormalMode)
+
+	if buf.UndoStack != nil {
+		buf.UndoStack.EndBlock(win.Cursor)
+	}
+
+	return nil
+}
+
+type EnterReplace struct {
+	Count int
+}
+
+func (a EnterReplace) WithCount(n int) Action {
+	a.Count = n
+	return a
+}
+
+func (a EnterReplace) Execute(m Model) tea.Cmd {
+	m.SetMode(core.ReplaceMode)
+	return nil
+}
+
+type ReplaceModeChar struct {
+	Char string
+}
+
+// ReplaceModeChar.Execute: Inserts a single character at the cursor position, overwriting current
+// character.
+func (a ReplaceModeChar) Execute(m Model) tea.Cmd {
+	win := m.ActiveWindow()
+	buf := m.ActiveBuffer()
+
+	x, y := win.Cursor.Col, win.Cursor.Line
+	l := buf.Line(y)
+	if x < len(l) {
+		buf.SetLine(y, l[:x]+a.Char+l[x+1:])
+	} else {
+		buf.SetLine(y, l+a.Char)
+	}
+	win.SetCursorCol(x + len(a.Char))
+	return nil
+}
+
+// ReplaceNewline splits the current line at the cursor (enter key)
+type ReplaceNewline struct{}
+
+// ReplaceNewline.Execute: Splits the current line at the cursor (Enter key).
+func (a ReplaceNewline) Execute(m Model) tea.Cmd {
+	win := m.ActiveWindow()
+	buf := m.ActiveBuffer()
+
+	x, y := win.Cursor.Col, win.Cursor.Line
+	l := buf.Line(y)
+	if x == len(l) {
+		buf.InsertLine(y+1, "")
+	} else {
+		buf.SetLine(y, l[:x])
+		buf.InsertLine(y+1, l[x+1:])
+	}
+	win.SetCursorPos(y+1, 0)
+	return nil
+}
+
+// ReplaceTab inserts spaces equal to the tab size
+type ReplaceTab struct{}
+
+// ReplaceTab.Execute: Inserts spaces equal to the tab size (Tab key).
+func (a ReplaceTab) Execute(m Model) tea.Cmd {
+	win := m.ActiveWindow()
+	buf := m.ActiveBuffer()
+
+	x, y := win.Cursor.Col, win.Cursor.Line
+	l := buf.Line(y)
+	tabs := strings.Repeat(" ", m.Settings().TabStop)
+	if x < len(l) {
+		buf.SetLine(y, l[:x]+tabs+l[x+1:])
+	} else {
+		buf.SetLine(y, l+tabs)
+	}
+	win.SetCursorCol(x + len(tabs))
+	return nil
+}

internal/core/mode.go

@@ -11,13 +11,15 @@ const (
 	VisualMode
 	VisualLineMode
 	VisualBlockMode
+	ReplaceMode
+	WaitingMode // Same as NORMAL output, but cursor is the REPLACE cursor
 )
 
 // Mode.ToString: Returns a human-readable string representation of the mode
 // for display in the status bar.
 func (m Mode) ToString() string {
 	switch m {
-	case NormalMode:
+	case NormalMode, WaitingMode:
 		return "NORMAL"
 	case InsertMode:
 		return "INSERT"
@@ -29,6 +31,8 @@ func (m Mode) ToString() string {
 		return "V-LINE"
 	case VisualBlockMode:
 		return "V-BLOCK"
+	case ReplaceMode:
+		return "REPLACE"
 	default:
 		return "-----"
 	}

internal/editor/helpers_test.go

@@ -34,6 +34,16 @@ func sendKeys(tm *teatest.TestModel, keys ...string) {
 			tm.Send(tea.KeyMsg{Type: tea.KeyCtrlR})
 		case "ctrl+w":
 			tm.Send(tea.KeyMsg{Type: tea.KeyCtrlW})
+		case "tab":
+			tm.Send(tea.KeyMsg{Type: tea.KeyTab})
+		case "left":
+			tm.Send(tea.KeyMsg{Type: tea.KeyLeft})
+		case "right":
+			tm.Send(tea.KeyMsg{Type: tea.KeyRight})
+		case "up":
+			tm.Send(tea.KeyMsg{Type: tea.KeyUp})
+		case "down":
+			tm.Send(tea.KeyMsg{Type: tea.KeyDown})
 		default:
 			tm.Send(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune(key)})
 		}

internal/editor/integration_motion_jump_test.go

@@ -176,7 +176,7 @@ func TestMoveToLineEnd(t *testing.T) {
 		sendKeys(tm, "$")
 
 		m := getFinalModel(t, tm)
-		want := len(lines[0])
+		want := len(lines[0]) - 1
 		if m.ActiveWindow().Cursor.Col != want {
 			t.Errorf("CursorX() = %d, want %d", m.ActiveWindow().Cursor.Col, want)
 		}
@@ -188,7 +188,7 @@ func TestMoveToLineEnd(t *testing.T) {
 		sendKeys(tm, "$")
 
 		m := getFinalModel(t, tm)
-		want := len(lines[0])
+		want := len(lines[0]) - 1
 		if m.ActiveWindow().Cursor.Col != want {
 			t.Errorf("CursorX() = %d, want %d", m.ActiveWindow().Cursor.Col, want)
 		}
@@ -200,7 +200,7 @@ func TestMoveToLineEnd(t *testing.T) {
 		sendKeys(tm, "$")
 
 		m := getFinalModel(t, tm)
-		want := len(lines[0])
+		want := len(lines[0]) - 1
 		if m.ActiveWindow().Cursor.Col != want {
 			t.Errorf("CursorX() = %d, want %d", m.ActiveWindow().Cursor.Col, want)
 		}

internal/editor/integration_visual_test.go

@@ -398,9 +398,8 @@ func TestVisualModeJumpMotions(t *testing.T) {
 		if m.ActiveWindow().Anchor.Col != 0 {
 			t.Errorf("AnchorX() = %d, want 0", m.ActiveWindow().Anchor.Col)
 		}
-		// $ moves past end of line
-		if m.ActiveWindow().Cursor.Col != 11 {
-			t.Errorf("CursorX() = %d, want 11", m.ActiveWindow().Cursor.Col)
+		if m.ActiveWindow().Cursor.Col != 10 {
+			t.Errorf("CursorX() = %d, want 10", m.ActiveWindow().Cursor.Col)
 		}
 	})
 

internal/editor/model_builder.go

@@ -11,76 +11,7 @@ type ModelBuilder struct {
 	model Model
 }
 
-// RPGLE
-// abap
-// algol
-// algol_nu
-// arduino
-// ashen
-// aura-theme-dark
-// aura-theme-dark-soft
-// autumn
-// average
-// base16-snazzy
-// borland
-// bw
-// catppuccin-frappe
-// catppuccin-latte
-// catppuccin-macchiato
-// catppuccin-mocha
-// colorful
-// doom-one
-// doom-one2
-// dracula
-// emacs
-// evergarden
-// friendly
-// fruity
-// github
-// github-dark
-// gruvbox
-// gruvbox-light
-// hr_high_contrast
-// hrdark
-// igor
-// lovelace
-// manni
-// modus-operandi
-// modus-vivendi
-// monokai
-// monokailight
-// murphy
-// native
-// nord
-// nordic
-// onedark
-// onesenterprise
-// paraiso-dark
-// paraiso-light
-// pastie
-// perldoc
-// pygments
-// rainbow_dash
-// rose-pine
-// rose-pine-dawn
-// rose-pine-moon
-// rrt
-// solarized-dark
-// solarized-dark256
-// solarized-light
-// swapoff
-// tango
-// tokyonight-day
-// tokyonight-moon
-// tokyonight-night
-// tokyonight-storm
-// trac
-// vim
-// vs
-// vulcan
-// witchhazel
-// xcode
-// xcode-dark
+// NewModelBuilder: Builds and returns a new model, using the default color scheme (kanagawa-wave).
 func NewModelBuilder() *ModelBuilder {
 	chromaStyle := styles.Get("kanagawa-wave")
 

internal/input/handler.go

@@ -41,6 +41,7 @@ type Handler struct {
 	normalKeymap  *Keymap
 	visualKeymap  *Keymap
 	insertKeymap  *Keymap
+	replaceKeymap *Keymap
 	commandKeymap *Keymap
 
 	currentKeymap *Keymap
@@ -53,6 +54,7 @@ func NewHandler() *Handler {
 		normalKeymap:  NewNormalKeymap(),
 		visualKeymap:  NewVisualKeymap(),
 		insertKeymap:  NewInsertKeymap(),
+		replaceKeymap: NewReplaceKeymap(),
 		commandKeymap: NewCommandKeymap(),
 		currentKeymap: nil,
 	}
@@ -77,7 +79,7 @@ func (h *Handler) Handle(m action.Model, key string) tea.Cmd {
 
 		h.recordingKeys = []string{} // Clear recording on ESC
 		h.Reset()
-		if m.Mode() == core.InsertMode {
+		if m.Mode() == core.InsertMode || m.Mode() == core.ReplaceMode {
 			// Before exiting insert mode, end the block in the undo stack
 			win := m.ActiveWindow()
 			buf := m.ActiveBuffer()
@@ -95,6 +97,8 @@ func (h *Handler) Handle(m action.Model, key string) tea.Cmd {
 	switch m.Mode() {
 	case core.InsertMode:
 		return h.handleInsertKey(m, key)
+	case core.ReplaceMode:
+		return h.handleReplaceKey(m, key)
 	case core.CommandMode:
 		return h.handleCommandKey(m, key)
 	}
@@ -172,6 +176,9 @@ func (h *Handler) Handle(m action.Model, key string) tea.Cmd {
 func (h *Handler) dispatch(m action.Model, kind string, binding any, key string) tea.Cmd {
 	// Handle character motions (f/t/F/T) - transition to waiting state
 	if kind == "char_motion" {
+		if key == "r" {
+			m.SetMode(core.WaitingMode)
+		}
 		h.charMotionType = key
 		h.state = StateWaitingForChar
 		return nil
@@ -362,7 +369,11 @@ func (h *Handler) handleCharMotion(m action.Model, key string) tea.Cmd {
 
 	// Apply count if supported
 	if r, ok := mot.(action.Repeatable); ok {
-		mot = r.WithCount(count).(action.Motion)
+		result := r.WithCount(count)
+		// WithCount returns Action, but char motions still implement Motion
+		if m, ok := result.(action.Motion); ok {
+			mot = m
+		}
 	}
 
 	// If operator pending (e.g., "df{char}"), get range and operate
@@ -378,7 +389,14 @@ func (h *Handler) handleCharMotion(m action.Model, key string) tea.Cmd {
 
 	// Otherwise just execute the motion
 	cmd := h.executeMotion(m, mot)
+
+	// ReplaceChar modifies the buffer, so it should be repeatable with '.'
+	// (unlike f/t/F/T which are pure motions)
+	if _, isReplace := mot.(action.ReplaceChar); isReplace {
+		h.RecordAndReset(m)
+	} else {
 		h.Reset()
+	}
 	return cmd
 }
 
@@ -556,6 +574,32 @@ func (h *Handler) handleInsertKey(m action.Model, key string) tea.Cmd {
 	return action.InsertChar{Char: key}.Execute(m)
 }
 
+func (h *Handler) handleReplaceKey(m action.Model, key string) tea.Cmd {
+	buf := m.ActiveBuffer()
+	win := m.ActiveWindow()
+
+	// Start undo block on first insert key
+	if buf.UndoStack != nil && !buf.UndoStack.Recording() {
+		buf.UndoStack.BeginBlock(win.Cursor)
+	}
+
+	// Record the key for count replay (e.g. 5i...)
+	m.SetInsertKeys(append(m.InsertKeys(), key))
+	m.SetLastChangeKeys(append(m.LastChangeKeys(), key))
+
+	// Check the insert keymap first
+	kind, binding := h.replaceKeymap.Lookup(key)
+	switch kind {
+	case "action":
+		return binding.(action.Action).Execute(m)
+	case "motion":
+		return binding.(action.Motion).Execute(m)
+	}
+
+	// Fallback: treat as a regular character to "insert"
+	return action.ReplaceModeChar{Char: key}.Execute(m)
+}
+
 // Handler.handleCommandKey: Processes a keypress in command mode, executing
 // it as an action or inserting it into the command line. This does not record
 // anything into the undo stack.

internal/input/keymap.go

@@ -77,12 +77,14 @@ func NewNormalKeymap() *Keymap {
 			"u":      action.Undo{},
 			"ctrl+r": action.Redo{},
 			".":      action.Repeat{Count: 1},
+			"R":      action.EnterReplace{},
 		},
 		charMotions: map[string]action.Motion{
 			"f": action.FindChar{Forward: true, Inclusive: true, Repeated: false},
 			"F": action.FindChar{Forward: false, Inclusive: true, Repeated: false},
 			"t": action.FindChar{Forward: true, Inclusive: false, Repeated: false},
 			"T": action.FindChar{Forward: false, Inclusive: false, Repeated: false},
+			"r": action.ReplaceChar{Count: 1},
 		},
 		modifiers: map[string]any{
 			"i": nil,
@@ -146,6 +148,8 @@ func NewVisualKeymap() *Keymap {
 			"X": operator.DeleteOperator{},
 			"y": operator.YankOperator{},
 			"c": operator.ChangeOperator{},
+			"s": operator.ChangeOperator{}, // Same as c in visual mode
+			"R": operator.ChangeOperator{}, // Seems to do the same thing
 		},
 		actions: map[string]action.Action{
 			"p": action.VisualPaste{Count: 1, Replace: true},
@@ -202,7 +206,26 @@ func NewInsertKeymap() *Keymap {
 			"ctrl+w":    action.InsertDeletePreviousWord{},
 		},
 	}
+}
 
+// NewReplaceKeymap: Creates a keymap for replace mode with editing actions. All actions
+func NewReplaceKeymap() *Keymap {
+	return &Keymap{
+		motions: map[string]action.Motion{
+			"down":  motion.MoveDown{Count: 1},
+			"up":    motion.MoveUp{Count: 1},
+			"left":  motion.MoveLeft{Count: 1},
+			"right": motion.MoveRight{Count: 1},
+		},
+		operators: map[string]action.Operator{}, // this will likely be empty
+		actions: map[string]action.Action{
+			"enter":     action.ReplaceNewline{},
+			"backspace": action.InsertBackspace{},
+			"delete":    action.InsertDelete{},
+			"tab":       action.ReplaceTab{}, // TODO: This needs replacing
+			"ctrl+w":    action.InsertDeletePreviousWord{},
+		},
+	}
 }
 
 // NewCommandKeymap: Creates a keymap for command mode with command line editing.

internal/motion/jump.go

@@ -50,7 +50,7 @@ type MoveToLineEnd struct{}
 func (a MoveToLineEnd) Execute(m action.Model) tea.Cmd {
 	win := m.ActiveWindow()
 	buf := m.ActiveBuffer()
-	win.SetCursorCol(buf.Lines[win.Cursor.Line].Len())
+	win.SetCursorCol(buf.Lines[win.Cursor.Line].Len() - 1)
 	return nil
 }
 

internal/style/style.go

@@ -15,6 +15,7 @@ type Styles struct {
 	CursorNormal  lipgloss.Style
 	CursorInsert  lipgloss.Style
 	CursorCommand lipgloss.Style
+	CursorReplace lipgloss.Style
 
 	// Gutter (line numbers)
 	Gutter            lipgloss.Style
@@ -47,6 +48,7 @@ func DefaultStyles() Styles {
 		CursorNormal:  lipgloss.NewStyle().Reverse(true),
 		CursorInsert:  lipgloss.NewStyle().Underline(true),
 		CursorCommand: lipgloss.NewStyle().Reverse(true),
+		CursorReplace: lipgloss.NewStyle().Underline(true),
 
 		Gutter: lipgloss.NewStyle().
 			Background(lipgloss.Color("236")).
@@ -95,12 +97,17 @@ func ChromaStyles(chromaStyle *chroma.Style) Styles {
 
 		CursorInsert: lipgloss.NewStyle().
 			Background(lipgloss.Color(bgString)).
+			Bold(true).
 			Underline(true),
 
 		CursorCommand: lipgloss.NewStyle().
 			Background(lipgloss.Color(bgString)).
 			Reverse(true),
 
+		CursorReplace: lipgloss.NewStyle().
+			Background(lipgloss.Color(bgString)).
+			Underline(true),
+
 		Gutter: lipgloss.NewStyle().
 			Background(lipgloss.Color(
 				darkenColor(lineNumbers.Background, 0.9).String()),
@@ -163,6 +170,8 @@ func (s Styles) DefaultCursorStyle(mode core.Mode) lipgloss.Style {
 		return s.CursorInsert
 	case core.CommandMode:
 		return s.CursorCommand
+	case core.ReplaceMode:
+		return s.CursorReplace
 	default:
 		return s.CursorNormal
 	}
@@ -177,6 +186,11 @@ func (s Styles) CursorStyle(mode core.Mode, style lipgloss.Style) lipgloss.Style
 		return lipgloss.NewStyle().
 			Background(style.GetForeground()).
 			Foreground(style.GetBackground())
+	case core.ReplaceMode, core.WaitingMode:
+		return lipgloss.NewStyle().
+			Background(style.GetBackground()).
+			Foreground(style.GetForeground()).
+			Underline(true)
 	default:
 		return lipgloss.NewStyle().
 			Background(s.BackgroundStyle.GetBackground()).