tree-sitter-language-injection.nvim

Neovim plugin for inline language injection and syntax highlighting using Tree-sitter.

Table Of Contents

• tree-sitter-language-injection.nvim
  • Table Of Contents
  • Overview
    • Why use this plugin?
  • Features
  • Examples
    • 1. Inline Comment Annotation
    • 2. Above-line Comment Annotation
  • Configuration
  • Installation
    • Requirements
    • Using Packer
    • Using Lazy
    • Setup
  • Built-in Language Support
  • Screenshots
  • Troubleshooting
    • Issue: Injection Highlighting Gets Replaced by LSP Semantic Highlighting
      • Disabling semantic highlighting
      • Disabling semantic highlighting for strings
  • Contributing & Language Support
  • License
  • Credits

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Overview

tree-sitter-language-injection.nvim automatically applies syntax highlighting to code snippets embedded as strings or comments in your code, based on inline language annotations. For example, SQL queries inside JavaScript/TypeScript strings can be highlighted as SQL if marked accordingly.

Why use this plugin?

• Improved readability for embedded code (e.g. SQL, HTML in JS/TS, Python, etc.)
• Customizable for any language and annotation style
• Seamless integration with nvim-treesitter

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Features

• Inline comment annotation: Add a comment at the start of a string with the language name to enable syntax highlighting for the embedded code.
• Above-line comment annotation: Place a comment above a string/variable with the language name to trigger the injection.
• Configurable injections: Easily extend or override language injections using Lua tables and custom Tree-sitter queries.
• Built-in support: Out-of-the-box support for Python, Rust, JavaScript, and TypeScript, including common web and data languages.

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Examples

1. Inline Comment Annotation

const select = `
--sql
SELECT * FROM user
WHERE active = 1
`;

Result:

---

2. Above-line Comment Annotation

// sql
const select = `
SELECT * FROM user
WHERE active = 1
`;

Result:

---

Configuration

You can add or override language injections by passing a table to setup. For example:

require("tree-sitter-language-injection").setup({
  javascript = {
    string = {
      langs = {
        { name = "sql", match = "^(\r\n|\r|\n)*-{2,}( )*{lang}" }
      },
      query = [[
        ; query
        ;; string {name} injection
        ((string_fragment) @injection.content
                        (#match? @injection.content "{match}")
                        (#set! injection.language "{name}"))
      ]]
    },
    comment = {
      langs = {
        { name = "sql", match = "^//+( )*{lang}( )*" }
      },
      query = [[
        ; query
        ;; comment {name} injection
        ((comment) @comment .
          (lexical_declaration
            (variable_declarator
              value: [
                (string(string_fragment)@injection.content)
                (template_string(string_fragment)@injection.content)
              ]@injection.content)
          )
          (#match? @comment "{match}")
          (#set! injection.language "{name}")
        )
      ]]
    }
  }
})

It's already built-in for many languages, but you can tinker with a language you need or create an issue and I will help if possible.

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Installation

Requirements

• Neovim >= 0.9.0
• nvim-treesitter must be installed and set up

Using Packer

use({ "dariuscorvus/tree-sitter-language-injection.nvim", after = "nvim-treesitter" })

Using Lazy

{
  "dariuscorvus/tree-sitter-language-injection.nvim",
  opts = {}, -- calls setup()
}

Setup

require("tree-sitter-language-injection").setup()

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Built-in Language Support

Host Language	Comment Inline	Comment Above	Supported Embedded
Python	✅	✅	SQL, JS, TS, HTML, CSS, Python
Rust	✅	✅	SQL, JS, TS, HTML, CSS, Python
JavaScript	✅	✅	SQL, JS, TS, HTML, CSS, Python
TypeScript	✅	✅	SQL, JS, TS, HTML, CSS, Python

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Screenshots

Before configuration:

Configuring:

After configuration:

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Troubleshooting

Issue: Injection Highlighting Gets Replaced by LSP Semantic Highlighting

Problem:
When you open a file, injected language highlighting works as expected at first. However, after your LSP (Language Server Protocol) attaches, Neovim's semantic highlighting takes over, and the injection highlighting from this plugin disappears.

Solution:
This happens because some LSP configurations (especially with Neovim's built-in LSP client) enable semanticTokensProvider, which can override Tree-sitter-based highlights—including those provided by this plugin. You can choose between disabling semantic highlighting or only the semantic highlighting for strings.

Disabling semantic highlighting

To fix this, you can disable semantic tokens in your LSP setup. For example, if you use nvim-lspconfig, add the following to your LSP configuration:

on_attach = function(client, bufnr)
  -- Disable semantic tokens to preserve Tree-sitter injection highlights
  client.server_capabilities.semanticTokensProvider = nil
end

You can add this to your on_attach function for the relevant language servers, or globally. After this change, your injected highlights should remain visible even after the LSP attaches.

Disabling semantic highlighting for strings

You can automatically disable semantic highlighting for strings when any LSP attaches by placing this in your Neovim configuration:

vim.api.nvim_create_autocmd("LspAttach", {
  callback = function(args)
    -- Only clear the LSP string highlight group to preserve injection highlights
    vim.api.nvim_set_hl(0, "@lsp.type.string", {})
  end,
})

Place this in your init.lua or a relevant plugin setup file.
This ensures that the workaround is applied for every LSP client, preserving Tree-sitter injection highlights for strings without disabling all semantic tokens.

References:

• Issue #12: injection gets replaced with semantic highlighting after lsp loads

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If you experience other issues, please check open issues or open a new one with detailed information.

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Contributing & Language Support

I welcome and encourage pull requests for:

• New language support (host languages)
• Additional embedded/injected languages
• Improvements to existing injections and matching

If you have a reasonable request or need help implementing new support, feel free to open an issue or pull request—I'm happy to assist!
Let's make this plugin work for as many languages and workflows as possible.

License

MIT

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Credits

Created by DariusCorvus.