Gim/FEATURES.md

# TextEditor Feature Checklist

## Normal Mode Motions

### Basic Movement
- [x] `h` - Move left
- [x] `j` - Move down
- [x] `k` - Move up
- [x] `l` - Move right

### Word Movement
- [x] `w` - Forward to start of word
- [x] `e` - Forward to end of word
- [x] `b` - Backward to start of word
- [x] `W` - Forward to start of WORD (whitespace-delimited)
- [x] `E` - Forward to end of WORD
- [ ] `B` - Backward to start of WORD
- [ ] `ge` - Backward to end of word

### Line Movement
- [x] `0` - Move to start of line
- [x] `$` - Move to end of line
- [x] `_` - Move to first non-whitespace
- [x] `^` - Move to first non-whitespace (alias for `_`)
- [x] `|` - Move to column N

### File Movement
- [x] `G` - Move to bottom of file (or line N with count)
- [x] `gg` - Move to top of file (or line N with count)
- [ ] `H` - Move to top of screen
- [ ] `M` - Move to middle of screen
- [ ] `L` - Move to bottom of screen

### Scroll
- [x] `ctrl+u` - Scroll up half page
- [x] `ctrl+d` - Scroll down half page
- [ ] `ctrl+b` - Scroll up full page
- [ ] `ctrl+f` - Scroll down full page
- [ ] `ctrl+y` - Scroll up one line
- [ ] `ctrl+e` - Scroll down one line
- [ ] `zz` - Center cursor on screen
- [ ] `zt` - Scroll cursor to top
- [ ] `zb` - Scroll cursor to bottom

### Search Movement
- [x] `f{char}` - Find char forward on line
- [x] `F{char}` - Find char backward on line
- [x] `t{char}` - Till char forward on line
- [x] `T{char}` - Till char backward on line
- [x] `;` - Repeat last f/F/t/T
- [x] `,` - Repeat last f/F/t/T reversed
- [ ] `/` - Search forward
- [ ] `?` - Search backward
- [ ] `n` - Next search result
- [ ] `N` - Previous search result
- [ ] `*` - Search word under cursor forward
- [ ] `#` - Search word under cursor backward

### Other Movement
- [ ] `%` - Jump to matching bracket
- [ ] `{` - Jump to previous paragraph
- [ ] `}` - Jump to next paragraph
- [ ] `(` - Jump to previous sentence
- [ ] `)` - Jump to next sentence

---

## Operators

### Implemented
- [x] `d` - Delete operator
- [x] `y` - Yank operator
- [x] `dd` - Delete line (double press)
- [x] `yy` - Yank line (double press)

### Not Implemented
- [x] `c` - Change operator
- [x] `cc` - Change line
- [ ] `>` - Indent right
- [ ] `<` - Indent left
- [ ] `=` - Auto-indent
- [ ] `gq` - Format text
- [ ] `gu` - Lowercase
- [ ] `gU` - Uppercase
- [ ] `g~` - Swap case
- [ ] `!` - Filter through external command

---

## Actions

### Insert Mode Entry
- [x] `i` - Insert before cursor
- [x] `a` - Insert after cursor
- [x] `I` - Insert at start of line
- [x] `A` - Insert at end of line
- [x] `o` - Open line below
- [x] `O` - Open line above
- [x] `s` - Substitute character (delete + insert)
- [x] `S` - Substitute line (delete line + insert)
- [x] `C` - Change to end of line
- [ ] `gi` - Insert at last insert position

### Delete Actions
- [x] `x` - Delete character under cursor
- [x] `D` - Delete to end of line
- [x] `X` - Delete character before cursor
- [ ] `J` - Join lines
- [ ] `gJ` - Join lines without space

### Yank/Paste
- [x] `p` - Paste after cursor
- [x] `P` - Paste before cursor
- [ ] `gp` - Paste after and move cursor to end
- [ ] `gP` - Paste before and move cursor to end

### Registers
- [x] Unnamed register (`"`)
- [x] Numbered registers (`0-9`)
- [x] Register types (charwise, linewise, blockwise)
- [ ] `"` - Register prefix (select register for next operation)
- [ ] Named registers (`a-z`)
- [ ] Append to named registers (`A-Z`)
- [ ] Black hole register (`_`)
- [ ] System clipboard (`+`, `*`)
- [ ] Expression register (`=`)
- [ ] Last search register (`/`)

### Undo/Redo
- [x] `u` - Undo
- [x] `ctrl+r` - Redo
- [x] `.` - Repeat last change
- [ ] `U` - Undo all changes on line

### Other Normal Mode
- [ ] `r{char}` - Replace character
- [ ] `R` - Replace mode
- [ ] `~` - Swap case of character
- [ ] `ctrl+a` - Increment number
- [ ] `ctrl+x` - Decrement number
- [ ] `q{reg}` - Record macro
- [ ] `@{reg}` - Play macro
- [ ] `@@` - Repeat last macro
- [x] `ctrl+c` - Quit (custom)

---

## Visual Mode

### Mode Entry
- [x] `v` - Character-wise visual mode
- [x] `V` - Line-wise visual mode
- [x] `ctrl+v` - Block-wise visual mode
- [ ] `gv` - Reselect last visual selection

### Visual Mode Operations
- [x] Motions work in visual mode
- [x] `d` / `x` - Delete selection
- [x] `y` - Yank selection
- [x] `c` - Change selection
- [ ] `>` - Indent selection
- [ ] `<` - Unindent selection
- [ ] `=` - Auto-indent selection
- [ ] `~` - Swap case of selection
- [ ] `u` - Lowercase selection
- [ ] `U` - Uppercase selection
- [ ] `J` - Join selected lines
- [ ] `o` - Go to other end of selection
- [ ] `O` - Go to other corner (block mode)

---

## Insert Mode

### Text Input
- [x] Character insertion
- [x] `Enter` - Insert newline
- [x] `Tab` - Insert tab/spaces
- [x] `Backspace` - Delete character before cursor
- [x] `Delete` - Delete character under cursor
- [x] `ctrl+w` - Delete word before cursor

### Movement in Insert Mode
- [x] Arrow keys (up/down/left/right)
- [ ] `ctrl+h` - Backspace (alias)
- [ ] `ctrl+j` - Insert newline (alias)
- [ ] `ctrl+t` - Indent line
- [ ] `ctrl+d` - Unindent line

### Exit Insert Mode
- [x] `Esc` - Exit to normal mode
- [ ] `ctrl+c` - Exit to normal mode
- [ ] `ctrl+[` - Exit to normal mode

---

## Command Mode

### Entry/Exit
- [x] `:` - Enter command mode
- [x] `Esc` - Exit command mode
- [x] `Enter` - Execute command

### Editing
- [x] Character input
- [x] `Backspace` - Delete character
- [x] `Delete` - Delete character
- [x] `ctrl+w` - Delete word
- [x] `Left` / `Right` - Move cursor

### Commands Implemented
- [x] `:set number` / `:set nonumber` - Toggle line numbers
- [x] `:set number!` - Toggle line numbers
- [x] `:set tabstop=N` - Set tab width
- [x] `:register {name}` - Show register contents
- [x] `:w` - Write file
- [x] `:q` - Quit
- [x] `:wq` - Write and quit
- [x] `:q!` - Force quit
- [x] `:e {file}` - Edit file
- [x] `:bn` / `:bp` - Next/previous buffer
- [ ] `:{range}` - Go to line
- [ ] `:%s/old/new/g` - Search and replace
- [ ] `:!{cmd}` - Run shell command
- [ ] `:help` - Show help

---

## Text Objects

### Implemented

- [x] `iw` / `aw` - Inner/around word
- [x] `iW` / `aW` - Inner/around WORD
- [x] `is` / `as` - Inner/around sentence
- [x] `ip` / `ap` - Inner/around paragraph
- [x] `i"` / `a"` - Inner/around double quotes
- [x] `i'` / `a'` - Inner/around single quotes
- [x] `` i` `` / `` a` `` - Inner/around backticks
- [x] `i(` / `a(` - Inner/around parentheses
- [x] `i[` / `a[` - Inner/around brackets
- [x] `i{` / `a{` - Inner/around braces
- [x] `i<` / `a<` - Inner/around angle brackets
### Not Implemented
- [ ] `it` / `at` - Inner/around tag

---

## Marks & Jumps

### Not Implemented
- [ ] `m{a-z}` - Set local mark
- [ ] `m{A-Z}` - Set global mark
- [ ] `` `{mark} `` - Jump to mark (exact position)
- [ ] `'{mark}` - Jump to mark (line start)
- [ ] ``` `` ``` - Jump to previous position
- [ ] `''` - Jump to previous line
- [ ] `` `. `` - Jump to last change
- [ ] `ctrl+o` - Jump back in jump list
- [ ] `ctrl+i` - Jump forward in jump list

---

## Buffers

Buffers are in-memory representations of files. A buffer exists for each open file.

### Buffer Model
- [x] Buffer struct (id, filename, lines, modified flag, cursor position)
- [x] Buffer list/manager
- [x] Current buffer tracking
- [ ] Buffer-local settings (tabstop, filetype, etc.)
- [x] Modified/dirty state tracking
- [x] Read-only buffer support

### Buffer Navigation
- [x] `:e {file}` - Edit file (open in new buffer or switch to existing)
- [x] `:bn` / `:bnext` - Next buffer
- [x] `:bp` / `:bprev` - Previous buffer
- [x] `:b {name}` - Switch to buffer by name (partial match)
- [x] `:b {number}` - Switch to buffer by number
- [x] `:bf` / `:bfirst` - First buffer
- [x] `:bl` / `:blast` - Last buffer
- [x] `:buffers` / `:ls` - List all buffers
- [ ] `ctrl+^` / `ctrl+6` - Switch to alternate (previous) buffer

### Buffer Operations
- [x] `:bd` / `:bdelete` - Delete buffer (close file)
- [x] `:bd!` - Force delete buffer (discard changes)
- [ ] `:bw` / `:bwipeout` - Wipe buffer (remove completely)
- [x] `:w` - Write current buffer to file
- [x] `:w {file}` - Write buffer to specific file
- [x] `:wa` - Write all modified buffers
- [ ] `:sav {file}` - Save as (write to new file, switch to it)

### Buffer State
- [ ] Track cursor position per buffer
- [ ] Track undo history per buffer
- [ ] Track marks per buffer
- [ ] Remember scroll position when switching
- [ ] Alternate buffer (`#`) tracking

### Buffer Indicators
- [x] `%` - Current buffer (in buffer list)
- [ ] `#` - Alternate buffer
- [ ] `a` - Active (loaded and visible)
- [ ] `h` - Hidden (loaded but not visible)
- [x] `l` - Loaded (active and hidden do not exist yet)
- [x] `+` - Modified
- [x] `-` - Read-only
- [ ] `=` - Readonly (cannot be modified) (?)

### Hidden Buffers
- [ ] `:set hidden` - Allow switching with unsaved changes
- [x] Prompt to save when closing modified buffer
- [x] `:q` behavior with modified buffers

### Argument List (Advanced)
- [ ] `:args` - Show argument list
- [ ] `:next` / `:prev` - Navigate argument list
- [ ] `:argadd` / `:argdelete` - Modify argument list

---

## Plugins / Extensions

### Harpoon (File Navigation)
- [ ] Quick file marks (1-4 files)
- [ ] Add file to list
- [ ] Navigate to marked file
- [ ] Show file list

### Telescope / Fuzzy Finder
- [ ] File picker
- [ ] Buffer picker
- [ ] Grep/search
- [ ] Command palette

### File Explorer
- [ ] Tree view
- [ ] File operations (create, delete, rename)
- [ ] Navigation

### LSP Support
- [ ] Go to definition
- [ ] Find references
- [ ] Hover information
- [ ] Diagnostics
- [ ] Code actions
- [ ] Completion

### Git Integration
- [ ] Git status
- [ ] Git diff
- [ ] Git blame
- [ ] Hunk navigation

### Other
- [ ] Multiple cursors
- [ ] Snippets
- [ ] Auto-pairs (brackets, quotes)
- [ ] Surround (change surrounding chars)
- [ ] Comment toggle
- [ ] Indentation guides
- [ ] Syntax highlighting
- [ ] Statusline customization
- [ ] Themes

---

## Editor Features

### Display
- [x] Line numbers
- [x] Cursor position tracking
- [x] Viewport/scrolling (Y)
- [ ] Viewport/scrolling (X)
- [x] ScrollOff setting
- [x] Relative line numbers
- [ ] Cursor line highlight
- [ ] Column highlight
- [ ] Wrap/nowrap
- [ ] Word wrap at window edge
- [ ] Show whitespace characters
- [ ] Color column (ruler)

### Files
- [x] File reading
- [x] File writing
- [ ] Auto-save
- [ ] Backup files
- [ ] Swap files
- [ ] File encoding
- [ ] Line endings (LF/CRLF)

### Search & Replace
- [ ] Incremental search
- [ ] Search highlighting
- [ ] Case sensitivity options
- [ ] Regex support
- [ ] Search and replace

### Misc
- [ ] Split windows
- [ ] Tabs
- [ ] Sessions
- [ ] Persistent undo
- [ ] Spell check

---

### Well Tested - Editor Core

#### Command Execution (179 tests)
- [x] Command parsing and validation
- [x] Command lookup and prefix matching
- [x] Force flag handling (!)
- [x] Write commands (`:w`, `:w {file}`, `:w!`)
- [x] Write all commands (`:wa`, `:wall`, `:wa!`)
- [x] Quit commands (`:q`, `:q!`, `:qa`, `:qa!`)
- [x] Write-quit commands (`:wq`, `:wq!`, `:wqa`, `:wqa!`)
- [x] Edit command (`:e {file}`)
- [x] Register display (`:register`, `:reg {name}`)
- [x] Set commands (`:set number`, `:set tabstop=N`, etc.)
- [x] Setting lookup and validation
- [x] Buffer-level readonly protection
- [x] Scratch buffer write protection
- [x] Force write bypassing readonly/scratch checks
- [x] Multiple buffer write operations
- [x] File write error handling (permissions, paths)
- [x] Modified buffer tracking
- [x] Unicode filename and content handling
- [x] Edge cases (empty args, long filenames, special chars)

#### Program Initialization (70 tests)
- [x] Empty program creation
- [x] File program with nonexistent files (new file buffers)
- [x] File program with existing files (content loading)
- [x] Line ending handling (Unix `\n`, Windows `\r\n`, mixed)
- [x] Tab to space conversion based on TabStop
- [x] Unicode content preservation (CJK, emoji)
- [x] File extension and type detection
- [x] Buffer state initialization (flags, metadata)
- [x] Large file handling (10,000+ lines)
- [x] Long line handling (10,000+ chars)
- [x] Empty file handling
- [x] Builder pattern method chaining
- [x] Program option accumulation
- [x] Model state defaults (settings, registers, mode)
- [x] Error handling (permissions, invalid paths)
- [x] Integration workflows (end-to-end)
- [x] Edge cases (empty filenames, relative paths, dot files)

### Moderately Tested
- [x] Basic motions (h, j, k, l)
- [x] Word motions (w, e, b)
- [x] Jump motions (G, gg, 0, $, _, ^, |)
- [x] Scroll actions (ctrl+u, ctrl+d)
- [x] Delete operator (d, dd)
- [x] Yank operator (y, yy)
- [x] Paste actions (p, P)
- [x] Change operator (c, cc, C)
- [x] Substitute action (s, S)
- [x] Insert mode entry (i, a, I, A, o, O)
- [x] Insert mode editing (enter, backspace, delete, tab, ctrl+w)
- [x] Visual modes (v, V, ctrl+v)
- [x] Visual mode with motions
- [x] Delete actions (x, D)
- [x] Register behavior