A Neovim plugin that makes switching between header & implementation files in C/C++ quick and painless.

Requirements

This should work with any version of Neovim that plenary currently supports.

Installation

Using vim-plug

Plug 'nvim-lua/plenary.nvim' " required dependency
Plug 'jakemason/ouroboros'

Using packer.nvim

use {
  'jakemason/ouroboros',
  requires = { {'nvim-lua/plenary.nvim'} }
}

You can run :checkhealth to verify the plugin and dependencies are installed correctly.

Then you can set custom weights for file extension preference matching if you'd like:

-- these are the defaults, customize as desired
require('ouroboros').setup({
    extension_preferences_table = {
          c = {h = 2, hpp = 1},
          h = {c = 2, cpp = 1},
          cpp = {hpp = 2, h = 1},
          hpp = {cpp = 1, c = 2},
    },
    -- if this is true and the matching file is already open in a pane, we'll
    -- switch to that pane instead of opening it in the current buffer
    switch_to_open_pane_if_possible = false,
})

If you don't call setup explicitly, the defaults above will be used. Thus, according to the table above, a file ending in ".c" will first look for a file ending in ".h" (weight of 2) before it looks for a match of ".hpp" (weight of 1).

You can get all of this information in the editor by running :help ouroboros.

Usage

Invoke the command :Ouroboros as needed, or bind it as desired:

" Example binding -- only works in a c/cpp file
autocmd! Filetype c,cpp map<buffer> <C-e> :Ouroboros<CR>

If you'd like to open the result in a split, simply pipe Ouroboros to vsplit or split:

autocmd! Filetype c,cpp noremap<buffer> <leader>sv :vsplit \| Ouroboros<CR> " open result in a vertical split
autocmd! Filetype c,cpp noremap<buffer> <leader>sh :split \| Ouroboros<CR>  " open result in a horizontal split

If a matching file isn't found, you'll be prompted to create one in the same directory as the file you called Ouroboros from. You can optionally edit the path and name, hitting enter to create the file and open it, or cancel and skip file creation entirely.

Example:

Manual typing of the command, followed by invoking it quickly via keystroke. This .gif is captured at 7FPS, so it'll be a lot smoother on your machine.

---

After the Ouroboros command is invoked, your working directory will be recursively searched until a file matching the same name with the counterpart extension is discovered. Note that the search also respects your .gitignore if one exists and any file ignored in git will be ignored in the results. As such, I suggest working from the root of your project. Once that file is found, it will automatically be opened in the current buffer. If no corresponding file is found, a message will be logged to the messages buffer -- use :messages to review your recent messages.

Assumptions

Ouroboros will only find a corresponding file if it has the same name and the counterpart extension. If multiple files with the same name and counterpart extension are found, the first result is opened. Conceivably in the future I'd like to present a window if more than one possible match is found and allow the user to pick from the list.

Debugging

Put let g:ouroboros_debug = 1 into your init.vim file to enable additional logging that will detail what Ouroboros is doing when running.

Why use this plugin? There's several other options that do this!

None of the alternatives worked well for me. I'd been using coc-clangd most recently and wasn't pleased with the results that calling :CocCommand clangd.switchSourceHeader would yield. Often the switch was noticeably delayed (1.0s or more) or I could switch from a header file to the implementation, but if I called switchSourceHeader again it would not switch back to the header, and vice versa. This was increasingly common if the folder structure of the project was several layers deep.

I'd also tried CurtineIncSw.vim and had similar problems: failure to find corresponding files in larger projects, slow performance, etc. Same thing with a.vim, and ctags solutions as well.

This solution is fast, doesn't require code analysis, and is easy to use.