Vi Mode for Fresh

Vi-style modal editing implemented as a TypeScript plugin with minimal core changes.

Design Philosophy

1. Plugin-based - Vi logic lives in plugins/vi_mode.ts, not Rust
2. Composable - Operators (d, c, y) work with any motion
3. Minimal core - Rust provides atomic actions, plugin handles mode logic
4. Community-friendly - TypeScript changes don't require recompilation

How It Works

Atomic Actions (Preferred)

For common operator+motion combinations, we use atomic Rust actions that perform the entire operation in one step. This avoids async timing issues.

const atomicOperatorActions = {
  d: {
    move_word_right: "delete_word_forward",
    move_word_left: "delete_word_backward",
    move_line_end: "delete_to_line_end",
    move_line_start: "delete_to_line_start",
  },
  y: {
    move_word_right: "yank_word_forward",
    move_word_left: "yank_word_backward",
    move_line_end: "yank_to_line_end",
    move_line_start: "yank_to_line_start",
  },
};

Selection-Based Fallback

For motions without atomic actions, we use selection-based approach:

function applyOperatorWithMotion(operator: string, motionAction: string) {
  editor.executeAction(selectAction);  // e.g., select_up, select_down
  editor.executeAction("cut");         // or "copy" for yank
}

This works because selections are synchronous within a single plugin action.

Batch Actions API

For efficient count prefix support (e.g., 3dw), we use executeActions which executes multiple actions in a single Rust call without roundtrips:

// Execute "move_down" 5 times efficiently
editor.executeActions([{ action: "move_down", count: 5 }]);

// Execute multiple actions in sequence
editor.executeActions([
  { action: "delete_word_forward", count: 3 },
  { action: "move_right" }
]);

Current Status

Working

Feature	Commands
Movement	h j k l, w b e, 0 $, gg G, Ctrl-f Ctrl-b
Count prefix	3j, 5w, 3dw, 2dd, 10x - works with motions, operators, and more
Operators	d c y + motions (dw, cw, etc.)
Line ops	dd cc yy, D C
Char ops	x X s
Find char	f t F T, ; ,
Visual mode	v (char), V (line), Ctrl-v (block) - select with motions, then d/c/y
Text objects	iw aw (word), i" a" i' a' (quotes), i( a( i{ a{ i[ a[ (brackets)
Insert	i a I A o O
Search	/ n N
Colon cmds	:w :q :wq :q! :e :sp :vs :bn :bp :<line> and more
Repeat	. - repeat last change (works with x, dd, dw, cw, insert, etc.)
Other	u Ctrl-r (undo/redo), p P (paste), % (bracket match)

Not Implemented

Feature	Priority	Notes
Registers	Low	"a, "b, named registers
Macros	Low	q, @

Colon Command Mode

Press : in normal mode to enter command mode. Type a command and press Enter to execute.

Supported Commands

Command	Aliases	Description
:w	:write	Save current file
:q	:quit	Close buffer (fails if modified)
:q!		Force close buffer (discard changes)
:wq	:x	Save and close buffer
:wa	:wall	Save all buffers
:qa	:qall	Close all buffers
:qa!		Force close all buffers
:wqa	:xa	Save all and quit
:e	:edit	Reload current file
:e <file>		Open file
:sp	:split	Horizontal split
:vs	:vsplit	Vertical split
:only		Close other splits
:new		New buffer in horizontal split
:vnew		New buffer in vertical split
:enew		New buffer in current split
:bn	:bnext	Next buffer
:bp	:bprev	Previous buffer
:bd	:bdelete	Close buffer
:ls	:buffers, :files	List buffers
:tabnew	:tabe	New tab/buffer
:tabn	:tabnext	Next tab
:tabp	:tabprev	Previous tab
:cn	:cnext	Next diagnostic
:cp	:cprev	Previous diagnostic
:copen	:cope	Open diagnostics panel
:<number>		Go to line number
:set nu	:set number	Show line numbers
:set nonu	:set nonumber	Hide line numbers
:noh	:nohlsearch	Clear search highlight
:pwd		Print working directory
:f	:file	Show file info
:version		Show version
:help	:h	Show help

Not Supported

• :!command - Shell commands (use terminal)
• :s/old/new/ - Substitute (use Ctrl+H for search/replace)
• :g/pattern/ - Global command
• Range prefixes (e.g., :%, :1,10)

Files

File	Purpose
plugins/vi_mode.ts	Plugin implementation (~900 lines)
src/input/buffer_mode.rs	Plugin mode key handling
src/services/plugins/runtime.rs	Core APIs for plugins
tests/e2e/vi_mode.rs	E2E tests

Usage

1. Open command palette (Ctrl+P)
2. Run "Toggle Vi mode"
3. Status bar shows current mode (-- NORMAL --, -- INSERT --)