serenity/Documentation/NvimConfiguration.md

# NVim Project Configuration

NVim can be configured to use the [COC-clangd](https://github.com/clangd/coc-clangd)
plugin to provide code-completion as well as inline
[git blame](https://github.com/f-person/git-blame.nvim) using [vim-plug](https://github.com/junegunn/vim-plug).

Make sure you ran `./Meta/serenity.sh rebuild-toolchain` as well as
`./Meta/serenity.sh run`.

# Install vim-plug

See [https://github.com/junegunn/vim-plug](https://github.com/junegunn/vim-plug).

# Install coc.nvim

The config file for neovim is at `~/.config/nvim/init.vim` or if
set `$XDG_CONFIG_HOME/nvim/init.vim`.

Add the Plugin:

```vim
Plug 'neoclide/coc.nvim', { 'branch': 'release' }
```

Run `:PlugInstall` inside nvim.

# Install coc-clangd via CocInstall

```vim
:CocInstall coc-clangd
```

> **Note**: This guide is tested with clangd version 14.0.6 and 15.0.6.

In case you have not installed clangd already install it with
`:CocCommand clangd.install`.

This will install a separate version of clangd just for neovim.

# Configure coc-clangd in coc-settings.json

Use the following settings to ensure that coc-clangd works out of the box.

> **Note**: You might want to adjust the `clangd.fallbackFlags` depending on your build
system and customize the `inlayHints.sep` based on your preference.

```json
{
    "clangd.fallbackFlags": ["-std=c++20"],
    "semanticTokens.enable": true,
    "inlayHint.subSeparator": "︴",
    "inlayHints.enableParameter": true,
    "clangd.inlayHints.sep": "⇝"
}
```

To change the coc-settings.json go to the file `~/.config/nvim/coc-settings.json`
or type `:CocConfig` in the command line.

> **Note**: In case you already had another c++ language server configured in the
`coc-settings.json` you might want to nuke it first and
work towards your desired config by adding the other parts back in to avoid
conflicts.

> **Note**: If you have configured `clangd` as a languageServer in
`coc-settings.json`, you should remove it to avoid running clangd twice!

> **Note**: `clangd.inlayHints.sep` breaks on `clangd 15.0.6`.

# Formatting
For code formatting the formatter plugin can be used.
```vim
Plug 'mhartington/formatter.nvim'
```
### Configuration
To use the formatter plugin one needs to opt-in to specific formatters. An example lua configuration which uses clang-format for cpp files:
```lua
require("formatter").setup{
    filetype = {
        cpp = {
            require("formatter.filetypes.cpp").clangformat
        }
    }
}
```

# Install git blame (Optional)

```vim
Plug 'f-person/git-blame.nvim'
```

Run `:PlugInstall` inside nvim.

# Configure your init.vim

The config file for neovim is at `~/.config/nvim/init.vim` or if
set `$XDG_CONFIG_HOME/nvim/init.vim`.

The `init.vim` excerpt:

```vim
"IMPORTANT: the leader key for <leader> keycombos
let mapleader = "\\"

"BEGIN: git blame (optional)
hi GitBlame guifg=#7b7b7b
let g:gitblame_date_format = '%d.%m.%y %H:%M'
let g:gitblame_highlight_group = 'GitBlame'
let g:gitblame_message_when_not_committed = 'You: Uncommitted changes'
let g:gitblame_message_template = '   <author> (<committer>), <date> <sha> • <summary>'
"END: git blame

"BEGIN: coc
"inline hints (depending on clangd version one or another gets used)
hi CocHintVirtualText guifg=#84afe0
hi CocInlayHint guifg=#84afe0 guibg=#393939
hi CocInlayHintParameter guifg=#84afe0 guibg=#393939
hi CocInlayHintType guifg=#89ddff guibg=#393939

"semantic highlighting
hi CocSemMethod guifg=#bfaa87 gui=bold
hi CocSemFunction guifg=#bfaaf7 gui=bold
hi CocSemParameter guifg=#a9bfd1 gui=underline
hi CocSemVariable guifg=#8edbdb
hi CocSemProperty guifg=#23ce6d
hi link CocSemEnumMember Constant
hi link CocSemEnum CocSemClass
hi Constant guifg=#f78c6c
hi CocSemClass guifg=#89ddff
hi Statement guifg=#c792ea
hi Type guifg=#db954a


"remap keys for applying refactor code actions (on warnings) (\re)
nmap <silent> <leader>re <Plug>(coc-codeaction-refactor)
xmap <silent> <leader>r  <Plug>(coc-codeaction-refactor-selected)
nmap <silent> <leader>r  <Plug>(coc-codeaction-refactor-selected)

"outline for file (\o)
nmap <silent><nowait> <leader>o :<C-u>CocList outline<cr>

"goto definition etc.
nmap <silent> gd <Plug>(coc-definition)
nmap <silent> gt <Plug>(coc-type-definition)
nmap <silent> gi <Plug>(coc-implementation)
nmap <silent> gr <Plug>(coc-references)

"coc rename (\rn)
nmap <leader>rn <Plug>(coc-rename)

"prev or next error
nmap <silent> [g <Plug>(coc-diagnostic-prev)
nmap <silent> ]g <Plug>(coc-diagnostic-next)

"confirm coc-suggestion with enter
imap <silent><expr> <CR> coc#pum#visible() ? coc#pum#confirm() : "\<CR>"

"ctrl+space for completion
imap <silent><expr> <c-space> coc#refresh()

"show documentation with ctrl+k
nmap <silent><c-k> :call ShowDocumentation()<CR>

"show documentation if it's available
function! ShowDocumentation()
  if CocAction('hasProvider', 'hover')
    call CocActionAsync('doHover')
  else
    call feedkeys('K', 'in')
  endif
endfunction

"coc-clangd switch between header and source
nmap <silent>gs :CocCommand clangd.switchSourceHeader vsplit<CR>
"END: coc
```

# Configure .clangd

> **Note**: Every time a new source is added or the compilation commands get adjusted
(through CMake) you need to rerun `./Meta/serenity.sh rebuild`.

Link `ln -s /path/to/serenity/Build/x86_64/compile_commands.json /path/to/serenity/compile_commands.json`.

Create `/path/to/serenity/.clangd` (replace `/path/to/serenity`
with your SerenityOS directory) with content of the clangd section in the
[VSCodeConfiguration.md](./VSCodeConfiguration.md).

> **Note**: You can add a `Remove` part, where you can remove unwanted flags
such as those that aren't supported by the current version of clang.