Nix Inline Code Highlighting

Highlights embedded languages inside Nix strings using a comment marker — analogous to @injection.language from nvim-treesitter, but for VSCode

Works alongside jnoortheen.nix-ide

Example

The /* lang */ marker goes immediately before the opening '' or ". Highlighting applies to both multi-line (''...'') and single-line ("...") Nix strings

Automatic triggers

Some strings highlight with no marker:

From nvim-treesitter queries

Mirrors the nvim-treesitter injection queries:

• attributes pre*/post*/*Phase/script → shell
• writeShellScript*/writeBash*/writeDash* → shell, writeFish* → fish, writeHaskell* → haskell, writeJS* → javascript, writePerl* → perl, writePy* → python, writeRust* → rust (the "name" argument must precede the string, an optional flat { } argument may sit in between, as in pkgs.writers)
• builtins.match "pat" str and any function whose name ends in match → regex for the first argument
• nixosTest/runTest with a testScript attribute → python, writeShellApplication with a text attribute → shell
• a config attribute placed after type = "lua" in the same attribute set → lua (home-manager Neovim plugins)

Custom extensions

• shell configs and hooks: *Extra (initExtra, envExtra, profileExtra), *ShellInit (interactiveShellInit, loginShellInit), *Commands? (buildCommand, resumeCommands, extraInstallCommands), *Hook (Disko), *Scripts? (darkman) → shell (multiline only)
• overrideAttrs concatenations: (previousAttrs.postPatch or "") + '' → shell
• runCommand* → shell (runCommand, runCommandLocal, runCommandCC with "name" and optional flat { })

The one-line triggers above need the opening quote on the same line as the trigger. Strings after a multi-line attribute set still need the comment marker.

Supported languages

bash/sh/shell/shellscript, python/py, javascript/js, typescript/ts, json, yaml/yml, toml, html, css, scss/sass, lua, ruby/rb, go/golang, rust/rs, cpp/c++/cxx, c, java, kotlin/kt, sql/postgresql/mysql, xml, markdown/md, dockerfile, nix, haskell/hs, php, perl/pl, powershell/ps1/pwsh, fish, zsh, regex/regexp, diff/patch, makefile/make, ini/conf/cfg, kdl

For highlighting to work, the corresponding language must be known to VSCode — usually either built-in or installed via a third-party extension (e.g. kdl-org.kdl for KDL)

Installation

• Marketplace: ext install barsikus007.nix-injection
• Open VSX (VSCodium / Cursor / Code-OSS): search for nix-injection in Extensions
• From .vsix: download the release from GitHub and code --install-extension nix-injection-<version>.vsix

Development

bun install
bun run generate  # regenerate syntaxes/nix-inline-injection.tmLanguage.json from scripts/generate.js
bun run test      # tokenize test.nix via vscode-textmate

code --install-extension $(nix build .#vsix --no-link --print-out-paths)/*.vsix

To add a new language — one entry in languages.json (single source of truth for the generator and the nix flake), then bun run generate. Issues or PRs are welcomed!