Editor Support & Tooling¶

MVL ships a language server, a syntax highlighter, a tree-sitter grammar and three editor integrations. This page is honest about which are published and which you install from source — several are the latter.

Everything below lives in mvl-lang/mvl-spec except the grammar, which has its own repository.

What is available today¶

Tool	Install	Where it comes from
Language server	`pip install mvl-lsp`	PyPI · mvl-lsp
Syntax highlighter	`pip install pygments-mvl`	PyPI · pygments-mvl
Neovim	git, via your plugin manager	mvl-spec `editors/nvim`
tree-sitter grammar	git submodule or clone	mvl-lang/tree-sitter-mvl
Zed	dev extension, from source	mvl-spec `editors/zed`
VS Code	build a VSIX, from source	mvl-spec `editors/vscode`

Zed and VS Code are not yet in their marketplaces. Zed extensions require a pull request to zed-industries/extensions; the VS Code publish pipeline exists but is gated pending Marketplace credentials. Both work from source today.

Language server — `mvl-lsp`¶

Compiler-backed diagnostics. Rather than reimplementing MVL's type rules, it shells out to mvl check --stdin --format=json, so the squiggles you see are exactly what the compiler reports — including refinement failures, effect mismatches and IFC violations.

pip install mvl-lsp
mvl-lsp --help

It needs mvl on your PATH. See Getting Started.

Syntax highlighting — `pygments-mvl`¶

A Pygments lexer. Pygments is the tokeniser behind mkdocs-material, Sphinx, Hugo/Chroma and Jupyter, so one install covers most of the documentation ecosystem.

pip install pygments-mvl
pygmentize -l mvl example.mvl

It registers under the mvl alias and claims *.mvl, so fenced blocks tagged mvl highlight automatically. This site uses it — every code block you see is lexed by it.

Its keyword tables are generated from grammar/grammar.ebnf, not hand-maintained, so it cannot fall behind the language. The distinction matters in practice: end, timeout, audit, self and old are contextual keywords — special in one syntactic position and ordinary identifiers everywhere else — so let end = 5; correctly highlights end as a variable.

Neovim¶

Install from git with your plugin manager. lazy.nvim:

{
  "mvl-lang/mvl-spec",
  ft = "mvl",
  config = function()
    require("mvl").setup()
  end,
}

You also need the tree-sitter grammar as a sibling checkout of mvl-spec — the plugin resolves it at runtime. :checkhealth mvl reports whether it found the grammar, the parser and mvl on your PATH.

Provides highlighting, indentation, folding and mvl-lsp registration.

Zed¶

The extension declares the grammar by commit, so Zed fetches tree-sitter-mvl for you. Install as a dev extension:

git clone https://github.com/mvl-lang/mvl-spec
# Zed: cmd-shift-p -> "zed: install dev extension" -> pick mvl-spec/editors/zed

Provides highlighting, indentation and mvl-lsp as a registered language server.

VS Code¶

Not on the Marketplace yet. Build and install locally:

git clone https://github.com/mvl-lang/mvl-spec
cd mvl-spec/editors/vscode
npx @vscode/vsce package
code --install-extension mvl-*.vsix

VS Code uses a TextMate grammar rather than tree-sitter, so its highlighting is regex-based and slightly coarser than the other editors'. Its keyword patterns are generated from the same EBNF.

tree-sitter grammar¶

mvl-lang/tree-sitter-mvl — the grammar consumed by Neovim and Zed. Bindings for C, Node, Python, Rust and Swift. Not yet published to npm or crates.io; clone or vendor it as a submodule.

git clone https://github.com/mvl-lang/tree-sitter-mvl
cd tree-sitter-mvl && tree-sitter generate && tree-sitter test

How these stay in sync¶

Every keyword table above — the Pygments lexer, the VS Code TextMate patterns, the tree-sitter highlight queries for both Neovim and Zed — is generated from one file: grammar/grammar.ebnf.

mvl-spec's CI regenerates all of them on every pull request and fails if any committed artifact differs. Editing a generated file directly is a build failure.

This is deliberate, and it is recent. These lists were hand-copied across five artifacts until spec 0.1.4, and all five had drifted — two of them highlighted labels the language does not have, and one highlighted a function-level modifier the grammar explicitly denies. Generation replaced a convention with a check.

Versions¶

Editor integrations and tools are versioned in lockstep with the spec. The version you install may lag the spec release if the relevant publish step has not run — the table at the top is the reliable statement of what exists.