(n)vi(m): Go plugins

The previous three posts covered all the basics I recommend when using nvim (or any vi(m) really). What's next are concrete plugins useful when programming in Go, specifically two plugins I use daily in nvim.

Please keep in mind that I use vim-plug for installing plugins, so in the subsections below I will only indicate the corresponding command to use for vim-plug for installing them, but don't worry both plugins support different ways to get them installed.

The next gist contains all the configuration I use for both vim-go and coc.nvim, in the subsections below I will give you more context about specific configuration.

1) fatih/vim-go

vim-go is nowadays the de-facto plugin for Go, it supports compiling, testing and executing Go programms, as well as running code coverage, looking up for documentation, symbol/definition declaration and more.

To install it use:

Plug 'fatih/vim-go', { 'do': ':GoInstallBinaries' }

The configuration I use maps some keys for compiling, testing and running code coverage using the leader key:

function! s:build_go_files()
  let l:file = expand('%')
  if l:file =~# '^\f\+_test\.go$'
    call go#test#Test(0, 1)
  elseif l:file =~# '^\f\+\.go$'
    call go#cmd#Build(0)
  endif
endfunction

autocmd FileType go nmap <leader>b :<C-u>call <SID>build_go_files()<CR>
autocmd FileType go nmap <Leader>c <Plug>(go-coverage-toggle)
autocmd FileType go nmap <leader>t <Plug>(go-test)

Also I use some new commands for working with alternate/test files:

autocmd Filetype go command! -bang A call go#alternate#Switch(<bang>0, 'edit')
autocmd Filetype go command! -bang AV call go#alternate#Switch(<bang>0, 'vsplit')
autocmd Filetype go command! -bang AS call go#alternate#Switch(<bang>0, 'split')
autocmd Filetype go command! -bang AT call go#alternate#Switch(<bang>0, 'tabe')

This give us the following commands:

• :A for replacing the current buffer with the alternate test go. So if the file is file.go then file_test.go will be loaded.
• :AV similar to :A but now using a vertical split.
• :AS similar to :A but now using a horizontal split.
• :AT similar to :A but now opens up a new tab.

Next, we have:

let g:go_list_type = "quickfix"    " error lists are of type quickfix
let g:go_fmt_command = "goimports" " automatically format and rewrite imports
let g:go_auto_sameids = 1          " highlight matching identifiers
let g:go_def_mapping_enabled = 0   " coc.vim will do `gd`

The configuration above allows you to do the the following:

• Errors use quickfix for displaying errors,
• goimports is automatically called when saving a file,
• Matching identifiers are highlighted when cursor is on their name, and
• To disable :GoDef when calling gd, this is so coc.nvim can take over.

Alternatives to vim-go includes plugins like govim and coc-go.

2) neoclide/coc.nvim

neoclide/coc.nvim is a plugin for adding autocompletion that supports language server protocol, and therefore supports gopls!

To install it, first make sure you install nodejs:

brew install nodejs

Then install the plugin:

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

The configuration below:

nmap <silent> gr <Plug>(coc-references)
nmap <silent> gi <Plug>(coc-implementation)
nmap <silent> rn <Plug>(coc-rename)

nnoremap <silent> K :call <SID>show_documentation()<CR>
function! s:show_documentation()
  if (index(['vim','help'], &filetype) >= 0)
    execute 'h '.expand('<cword>')
  else
    call CocAction('doHover')
  endif
endfunction

Let's you do the following:

• gr Lists all the references to the selected symbol, for example other types using said type,
• gi Works for interface types, it allows you to list types implementing selected interface,
• rn Works for types, it allows you to rename types, this is similar to :GoRename (but this one works), and
• Z displays documentation for the selected type.

I highly encourage you to take a look at the example vim configuration because there are some nice settings that could improve your vim performance.

An alternative plugin to to coc.nvim is Shougo/deoplete.nvim which also supports multiple programming languages.

Finally let's see vim-go and coc.nvim in actioa!

Quick show-and-tell of using both plugins: