VSNeo - Neovim for Visual Studio Gallery feed (extension)

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VSNeo — Neovim for Visual Studio

Visual Studio keeps its editor. Neovim is the brain behind it.

VSNeo embeds a real, headless Neovim inside Visual Studio and lets it drive the standard editor: modes, motions, operators, registers, marks, macros and the command line are executed by Neovim itself, while Visual Studio keeps rendering, IntelliSense, refactorings and undo. Not a C# reimplementation of Vim, and not a terminal in a tool window — the same nvim.exe you already have, speaking msgpack-rpc over a named pipe.

How is this different from VsVim?

VSNeo exists because of VsVim — it's the reason Vim users stay in Visual Studio, and .vsvimrc mappings port over nearly verbatim via :Vsc. Where VSNeo differs:

• VsVim reimplements Vim in C#; VSNeo embeds a real, headless Neovim. Operators, text objects, registers, macros and the command line are executed by Neovim itself, so there is no emulation layer to drift — :%s/a/b/g works end to end, with the preview and the undo transaction you expect.
• Your Neovim plugins come along — anything that lives in the buffer/motion layer (surround, commentary, text objects) loads from ~/.vsneo/pack.
• Your config is Vimscript/Lua, sourced from ~/.vsneorc / ~/.vsneorc.lua, so mappings carry over from your real Neovim setup.

What you get

• Real Vim semantics — modes, motions, operators, counts, registers, marks, macros, visual and replace mode — executed by Neovim against a mirrored buffer and applied back into Visual Studio as ordinary edits.
• . and macros include what you typed. Insert-mode text goes to Visual Studio, so VSNeo records it and replays it: cwfoo<Esc> then . repeats the whole change, and qa...q records the typing too.
• One undo history: Visual Studio's. u and Ctrl-R walk it, one press per Vim change (c3wXYZ<Esc> undoes in one u), so undoing a Roslyn rename or a format works as well. The undone text flashes briefly.
• A real : and / command line, drawn as a floating popup at the top of the window (the Ctrl+Q shape), with wildmenu completion. Long output (:map, :messages) opens in a pager with Vim's more-prompt keys.
• Search that is Neovim's regex engine, with matches highlighted in the editor, a [3/12] count beside the current match, and ticks on the scrollbar for matches and marks; yank flash on TextYankPost.
• Folding is Visual Studio outlining, driven by Vim keys — za, zo, zc, zR, zM, zj/zk work on the language service's regions, and zf creates a real collapsible region.
• Navigation history is Visual Studio's — Ctrl-O/Ctrl-I walk back and forward through F12, Find All References and error-list jumps, not only Vim motions.
• Window management that understands tab groups — Ctrl-W h/j/k/l moves between splits by frame geometry, :split/:vsplit/:q map to the Visual Studio commands that produce the same layout, Ctrl-6 walks most-recently-used documents, gb jumps to any tab by letter label. :e, :b, :bn/:bp open and switch documents in Visual Studio.
• A flash-style s jump with letter labels over visible matches, and labels on f/F/t/T when a line holds several matches.
• Visual Studio commands from mappings: :Vsc Some.Command runs anything from Tools > Options > Keyboard, so .vsvimrc mappings port nearly verbatim. gd, gD, gi, gr, [d, ]d, K, <leader>rn, <leader>ca, <leader>f are pre-wired to Roslyn navigation and refactorings.
• Register and mark peek — " lists Neovim's registers and ` / ' its marks, with one-line previews beside the caret, and a which-key style popup shows what a pending prefix can still become.
• A Telescope-style picker, built in — fuzzy file finder, live grep (plain/regex/fuzzy), workspace symbols, document outline, current-file lines and git-modified files with a real preview pane, powered by the native fff engine with frecency learning. Bound to Ctrl+Shift+Alt+O/I/G/L/,/B/M/R (files, grep, grep word, current file, symbols, outline, git modified, resume) - those work in insert mode too - plus <leader>sf/sg/sw/ss in normal mode. The engine runs in its own process, so it can never take Visual Studio down. Same engine and shared ranking database as the standalone SeekyVS extension - nothing else to install.
• Insert mode stays Visual Studio's — IntelliSense, snippets, Copilot and brace completion work untouched. Only Esc, Ctrl-W and Ctrl-O are claimed there, plus any insert mapping on a named key you define yourself (imap <Down> <Esc><Down>).
• Relative line numbers and a mode badge that follow 'number' and 'relativenumber', with the mode shown in the status bar.
• Cursor, motion and effects — a Neovide-style cursor trail, particle and cyberpunk effects, a custom cursor with per-mode colors and glow, smooth scrolling, a jump beacon, a mode-colored cursor line and presets (Blade Runner, The Matrix, Cyberpunk 2077). All of it, with previews: docs/visual-features.md.

Requirements

• Windows, Visual Studio 2022 17.14+ or Visual Studio 2026.
• Neovim — any recent build (developed against 0.12), nvim.exe on PATH or pointed at with VSNEO_NVIM_PATH.

Install

From the Visual Studio Marketplace, or grab the VSIX from a GitHub Release / the CI build on the Open VSIX Gallery.

Then open a code file and look for VSNeo: connected in the status bar.

Quickstart

1. Open any source file. You start in normal mode — the caret is a block.
2. gg, %, ci", vap, . — everything behaves as in Vim.
3. : and / open the floating command line; Tab completes.
4. :Vsc Edit.GoToBrace, or map it: nnoremap [{ :Vsc Edit.GotoBrace<CR> in ~/.vsneorc.

Configuration

VSNeo sources %USERPROFILE%\.vsneorc (Vimscript), then %USERPROFILE%\.vsneorc.lua (Lua), at startup if they exist. examples/vsneorc.vim is a full .vsvimrc ported to VSNeo, and examples/vsneorc.lua shows every option and the effect presets. Every setting, command and default mapping is listed in docs/options.md. Two porting notes:

• inoremap on printable keys can never fire — typed characters go to Visual Studio, not Neovim. Insert mappings on named keys work: imap <Left> <Esc> and friends are claimed from Visual Studio and executed by Neovim itself (string, Lua-callback, and expr rhs all supported). Only mappings from your own rc are claimed — Neovim's defaults and everyone else's insert mode are untouched.
• Ctrl+Alt(+Shift) chords are never claimed — that is AltGr on many layouts and Visual Studio's own binding namespace.

Plugins live under %USERPROFILE%\.vsneo\pack\<group>\start\<plugin> (loaded at startup) or ...\opt\<plugin> (:packadd-able). Your regular Neovim plugins are deliberately not loaded; UI plugins draw to a grid nothing displays and cannot work here.

Troubleshooting

• Lifecycle diagnostics go to %TEMP%\vsneo.log — check there first.
• set VSNEO_TRACE_KEYS=1 before launching Visual Studio logs every key decision (Debug builds only). It answers the only question the outside cannot: did the key reach the extension at all.
• If Neovim isn't found, set VSNEO_NVIM_PATH=C:\path\to\nvim.exe.

Development

You need Windows, Visual Studio 2022 17.14+ or 2026 with the Visual Studio extension development workload, the .NET 10 SDK (for the Seeky picker's engine), and Neovim on PATH.

git clone --recurse-submodules https://github.com/knilecrack/VSNeo.git
cd VSNeo
start VSNeo.slnx

Press F5 to launch an experimental instance (/rootsuffix Exp) with the extension deployed. Deploy with F5, not from the command line: msbuild builds the VSIX but doesn't install it, and VSIXInstaller doesn't trigger the extension rescan — both fail silently and you test an old build.

Command-line build (from a Developer Command Prompt, where msbuild is on PATH):

msbuild VSNeo.slnx -restore -p:Configuration=Debug

dotnet build is not sufficient — the project references the Visual Studio SDK and WPF assemblies that require MSBuild.

Tests: pwsh tests/run-tests.ps1 runs the Lua companion suites against a headless Neovim. dotnet test tests/dotnet/VSNeo.Tests runs the C# unit tests (msgpack codec, stream framing, UTF-8 ↔ UTF-16 columns, the nvim → Visual Studio line edits) on .NET 8 — no Visual Studio needed, so they run on Linux and macOS too.

The Seeky picker's shared code comes from the external/Seeky submodule (clone with --recurse-submodules, or run git submodule update --init). Building it, taking changes from the Seeky repo and installing a local build into your normal Visual Studio: docs/seeky.md and docs/seeky-development.md.

Design rationale, the key-path invariant and the known landmines live in CLAUDE.md; AGENTS.md is the contributor/agent guide with the project layout and conventions.

How it works, in one paragraph

A KeyProcessor and an IOleCommandTarget filter intercept keystrokes and decide swallow-vs-passthrough from a locally cached mode — zero I/O on the key path. The effect travels over msgpack-rpc to a headless Neovim (--headless --listen \\.\pipe\vsneo-<guid>), which edits a mirrored buffer; buffer, cursor, viewport, mode, command line and search state stream back as RPC notifications and are applied to the Visual Studio editor. A companion Lua script (Lua/vsneo.lua) inside Neovim pushes the state the redraw protocol doesn't carry.

License

MIT