Go Development With Vim

Photo by Luca Bravo on Unsplash

If you are a Go developer or learning Go and want to use Vim, this tutorial will help you with a basic setup.

In this tutorial, we need 2 plugins.
vim-go: Go support for Vim
coc: Code completion

Install vim-plug, vim plugin-manager

curl -fLo ~/.vim/autoload/plug.vim — create-dirs \
 https://raw.githubusercontent.com/junegunn/vim-plug/master/plug.vim

To install plugins open your ~/.vimrc file and add these lines

call plug#begin(‘~/.vim/plugged’)
Plug ‘fatih/vim-go’
Plug ‘neoclide/coc.nvim’, {‘branch’: ‘release’}
call plug#end()
:PlugInstall

to install plugins

Now we need to configure plugins
•vim-go

:GoInstallBinaries

to install all necessary binaries for vim-go

•Coc

:CocConfig

to open a settings file for coc.

Paste these lines and save the file.

{
    "languageserver": {
        "golang": {
        "command": "gopls",
        "rootPatterns": ["go.mod", ".vim/", ".git/", ".hg/"],
        "filetypes": ["go"]
        }
    }
}

Disabling vim-go mapping `gd` for go to definition add this line to your ~/.vimrc

let g:go_def_mapping_enabled = 0

Finally some configuration for coc easier to work with. I copied the configurations from their Github page.

“ TextEdit might fail if hidden is not set.
set hidden
“ Some servers have issues with backup files, see #649.
set nobackup
set nowritebackup
“ Give more space for displaying messages.
set cmdheight=2
“ Having longer updatetime (default is 4000 ms = 4 s) leads to noticeable
“ delays and poor user experience.
set updatetime=300
“ Don’t pass messages to |ins-completion-menu|.
set shortmess+=c
“ Always show the signcolumn, otherwise it would shift the text each time
“ diagnostics appear/become resolved.
set signcolumn=yes
“ Use tab for trigger completion with characters ahead and navigate.
“ NOTE: Use command ‘:verbose imap <tab>’ to make sure tab is not mapped by
“ other plugin before putting this into your config.
inoremap <silent><expr> <TAB>
 \ pumvisible() ? “\<C-n>” :
 \ <SID>check_back_space() ? “\<TAB>” :
 \ coc#refresh()
inoremap <expr><S-TAB> pumvisible() ? “\<C-p>” : “\<C-h>”
function! s:check_back_space() abort
 let col = col(‘.’) — 1
 return !col || getline(‘.’)[col — 1] =~# ‘\s’
endfunction
“ Use <c-space> to trigger completion.
inoremap <silent><expr> <c-space> coc#refresh()
“ Use <cr> to confirm completion, `<C-g>u` means break undo chain at current
“ position. Coc only does snippet and additional edit on confirm.
“ <cr> could be remapped by other vim plugin, try `:verbose imap <CR>`.
if exists(‘*complete_info’)
 inoremap <expr> <cr> complete_info()[“selected”] != “-1” ? “\<C-y>” : “\<C-g>u\<CR>”
else
 inoremap <expr> <cr> pumvisible() ? “\<C-y>” : “\<C-g>u\<CR>”
endif
“ Use `[g` and `]g` to navigate diagnostics
nmap <silent> [g <Plug>(coc-diagnostic-prev)
nmap <silent> ]g <Plug>(coc-diagnostic-next)
“ GoTo code navigation.
nmap <silent> gd <Plug>(coc-definition)
nmap <silent> gy <Plug>(coc-type-definition)
nmap <silent> gi <Plug>(coc-implementation)
nmap <silent> gr <Plug>(coc-references)
“ Use K to show documentation in preview window.
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
“ Highlight the symbol and its references when holding the cursor.
autocmd CursorHold * silent call CocActionAsync(‘highlight’)
“ Symbol renaming.
nmap <leader>rn <Plug>(coc-rename)
“ Formatting selected code.
xmap <leader>f <Plug>(coc-format-selected)
nmap <leader>f <Plug>(coc-format-selected)
augroup mygroup
 autocmd!
 “ Setup formatexpr specified filetype(s).
 autocmd FileType typescript,json setl formatexpr=CocAction(‘formatSelected’)
 “ Update signature help on jump placeholder.
 autocmd User CocJumpPlaceholder call CocActionAsync(‘showSignatureHelp’)
augroup end
“ Applying codeAction to the selected region.
“ Example: `<leader>aap` for current paragraph
xmap <leader>a <Plug>(coc-codeaction-selected)
nmap <leader>a <Plug>(coc-codeaction-selected)
“ Remap keys for applying codeAction to the current line.
nmap <leader>ac <Plug>(coc-codeaction)
“ Apply AutoFix to problem on the current line.
nmap <leader>qf <Plug>(coc-fix-current)
“ Map function and class text objects
“ NOTE: Requires ‘textDocument.documentSymbol’ support from the language server.
xmap if <Plug>(coc-funcobj-i)
omap if <Plug>(coc-funcobj-i)
xmap af <Plug>(coc-funcobj-a)
omap af <Plug>(coc-funcobj-a)
xmap ic <Plug>(coc-classobj-i)
omap ic <Plug>(coc-classobj-i)
xmap ac <Plug>(coc-classobj-a)
omap ac <Plug>(coc-classobj-a)
“ Use CTRL-S for selections ranges.
“ Requires ‘textDocument/selectionRange’ support of LS, ex: coc-tsserver
nmap <silent> <C-s> <Plug>(coc-range-select)
xmap <silent> <C-s> <Plug>(coc-range-select)
“ Add `:Format` command to format current buffer.
command! -nargs=0 Format :call CocAction(‘format’)
“ Add `:Fold` command to fold current buffer.
command! -nargs=? Fold :call CocAction(‘fold’, <f-args>)
“ Add `:OR` command for organize imports of the current buffer.
command! -nargs=0 OR :call CocAction(‘runCommand’, ‘editor.action.organizeImport’)
“ Add (Neo)Vim’s native statusline support.
“ NOTE: Please see `:h coc-status` for integrations with external plugins that
“ provide custom statusline: lightline.vim, vim-airline.
set statusline^=%{coc#status()}%{get(b:,’coc_current_function’,’’)}
“ Mappings using CoCList:
“ Show all diagnostics.
nnoremap <silent> <space>a :<C-u>CocList diagnostics<cr>
“ Manage extensions.
nnoremap <silent> <space>e :<C-u>CocList extensions<cr>
“ Show commands.
nnoremap <silent> <space>c :<C-u>CocList commands<cr>
“ Find symbol of current document.
nnoremap <silent> <space>o :<C-u>CocList outline<cr>
“ Search workspace symbols.
nnoremap <silent> <space>s :<C-u>CocList -I symbols<cr>
“ Do default action for next item.
nnoremap <silent> <space>j :<C-u>CocNext<CR>
“ Do default action for previous item.
nnoremap <silent> <space>k :<C-u>CocPrev<CR>
“ Resume latest coc list.
nnoremap <silent> <space>p :<C-u>CocListResume<CR>