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10 days ago

Neogen - Your Annotation Toolkit

Neovim Lua

Table Of Contents


  • Create annotations with one keybind, and jump your cursor in the inserted annotation
  • Defaults for multiple languages and annotation conventions
  • Extremely customizable and extensible
  • Written in lua (and uses Tree-sitter)



Have Tree-sitter parsers installed on your system. For more information, check out the :treesitter-parsers neovim help page.


Use your favorite package manager to install Neogen, e.g:


    config = true,
    -- Uncomment next line if you want to follow only stable versions
    -- version = "*" 


use {
    config = function()
        require('neogen').setup {}
    -- Uncomment next line if you want to follow only stable versions
    -- tag = "*"


  • If you want to keep it simple, you can use the :Neogen command:
" will generate annotation for the function, class or other relevant type you're currently in
" or you can force a certain type of annotation with `:Neogen <TYPE>`
" It'll find the next upper node that matches the type `TYPE`
" E.g if you're on a method of a class and do `:Neogen class`, it'll find the class declaration and generate the annotation.
:Neogen func|class|type|...
  • If you like to use the lua API, I exposed a function to generate the annotations.

You can bind it to your keybind of choice, like so:

local opts = { noremap = true, silent = true }
vim.api.nvim_set_keymap("n", "<Leader>nf", ":lua require('neogen').generate()<CR>", opts)

Calling the generate function without any parameters will try to generate annotations for the current function.

You can provide some options for the generate, like so:

    type = "func" -- the annotation type to generate. Currently supported: func, class, type, file

For example, I can add an other keybind to generate class annotations:

local opts = { noremap = true, silent = true }
vim.api.nvim_set_keymap("n", "<Leader>nc", ":lua require('neogen').generate({ type = 'class' })<CR>", opts)

Snippet support

We added snippet support, and we provide defaults for some snippet engines. And this is done via the snippet_engine option in neogen's setup:

  • snippet_engine option will use provided engine to place the annotations:

Currently supported: luasnip, snippy, vsnip.

require('neogen').setup({ snippet_engine = "luasnip" })

That's all ! You can now use your favorite snippet engine to control the annotation, like jumping between placeholders.

Or, if you want to return the snippet as a string (to integrate with other snippet engines, for example), you can do it by using the return_snippet option in the generate function:

  • return_snippet option will return the annotations as lsp snippets.
local snippet, row, col = require('neogen').generate({ snippet_engine = "luasnip" })

And then pass the snippet to the plugin's snippet expansion function.

Default cycling support

Note that this part is only useful if you don't use the snippets integration.

If you don't want to use a snippet engine with Neogen, you can leverage Neogen's native jumps between placeholders. To map some keys to the cycling feature, you can do like so:

local opts = { noremap = true, silent = true }
vim.api.nvim_set_keymap("i", "<C-l>", ":lua require('neogen').jump_next<CR>", opts)
vim.api.nvim_set_keymap("i", "<C-h>", ":lua require('neogen').jump_prev<CR>", opts)

Or, if you want to use a key that's already used for completion purposes, take a look at the code snippet here:

local cmp = require('cmp')
local neogen = require('neogen')

cmp.setup {

    -- You must set mapping if you want.
    mapping = {
        ["<tab>"] = cmp.mapping(function(fallback)
            if neogen.jumpable() then
        end, {
        ["<S-tab>"] = cmp.mapping(function(fallback)
            if neogen.jumpable(true) then
        end, {


require('neogen').setup {
    enabled = true,             --if you want to disable Neogen
    input_after_comment = true, -- (default: true) automatic jump (with insert mode) on inserted annotation
    -- jump_map = "<C-e>"       -- (DROPPED SUPPORT, see [here](#cycle-between-annotations) !) The keymap in order to jump in the annotation fields (in insert mode)

If you're not satisfied with the default configuration for a language, you can change the defaults like this:

require('neogen').setup {
    enabled = true,
    languages = {
        lua = {
            template = {
                annotation_convention = "emmylua" -- for a full list of annotation_conventions, see supported-languages below,
                ... -- for more template configurations, see the language's configuration file in configurations/{lang}.lua

For example, if you want to quickly add support for new filetypes based around existing ones, you can do like this:

    languages = {
        ['cpp.doxygen'] = require('neogen.configurations.cpp')

Supported Languages

There is a list of supported languages and fields, with their annotation style

Languages Annotation Conventions Supported annotation types
sh Google Style Guide ("google_bash") func, file
c Doxygen ("doxygen") func, file, type
cs Xmldoc ("xmldoc") Doxygen ("doxygen") func, file, class
cpp Doxygen ("doxygen") func, file, class
go GoDoc ("godoc") func, type
java Javadoc ("javadoc) func, class
javascript JSDoc ("jsdoc") func, class, type, file
javascriptreact JSDoc ("jsdoc") func, class, type, file
kotlin KDoc ("kdoc") func, class
lua Emmylua ("emmylua") Ldoc ("ldoc") func, class, type, file
php Php-doc ("phpdoc") func, type, class
python Google docstrings ("google_docstrings") Numpydoc ("numpydoc") reST ("reST") func, class, type, file
ruby YARD ("yard") Rdoc ("rdoc") Tomdoc ("tomdoc") func, type, class
rust RustDoc ("rustdoc") Alternative ("rust_alternative") func, file, class
typescript JSDoc ("jsdoc") TSDoc ("tsdoc") func, class, type, file
typescriptreact JSDoc ("jsdoc") TSDoc ("tsdoc") func, class, type, file
vue JSDoc ("jsdoc") func, class, type, file

Adding Languages

  1. Using the defaults to generate a new language support: Adding Languages
  2. (advanced) Only if the defaults aren't enough, please see here: Advanced Integration

Tip: Take a look at this beatiful diagram, showing a representation of the codebase. You can then take a first understanding of what is under the hood. For more details, you can see :h neogen-develop.

Visualization of this repo






  • Binx, for making that gorgeous logo for free!


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