Install CoC extensions for java, python, C

vimrc

@@ -33,6 +33,11 @@ func OpenConfigFile(switch)
     endif
 endfunc
 
+function! s:check_back_space() abort
+    let col = col('.') - 1
+    return !col || getline('.')[col - 1]  =~# '\s'
+endfunction
+
 "---------- Basic ----------
 set nocompatible
 set noswapfile    "disable ugly .swp files
@@ -49,6 +54,8 @@ set noshowmode    "hide current Vim mode; will be available in lightlin
 call InstallVimPlug()
 call plug#begin('~/.vim/plugins')
 Plug 'gruvbox-community/gruvbox'
+" LSP configs
+":CocInstall coc-tsserver coc-python coc-json coc-java coc-clangd
 Plug 'neoclide/coc.nvim', {'branch': 'release'}
 Plug 'sheerun/vim-polyglot'
 Plug 'preservim/nerdtree'
@@ -105,11 +112,11 @@ let mapleader = ","
 nnoremap <leader>e :!pylint -E %<CR>
 noremap  <leader>w :call TrimTrailingWhiteSpaces()<CR>
 noremap <leader><space> :nohl<CR>
-nnoremap gb :Git blame<CR>
-nnoremap gd :Git diff %<CR>
-nnoremap gc :Git commit %<CR>
-execute "noremap <leader>t :botright terminal ++close ++rows=10 bash --rcfile ".s:bashrc."<CR>"
-execute "noremap <leader>p :botright terminal ++close ++rows=10 ".s:python."<CR>"
+nnoremap <leader>gb :Git blame<CR>
+nnoremap <leader>gd :Git diff %<CR>
+nnoremap <leader>gc :Git commit %<CR>
+execute "noremap <silent><leader>t :botright terminal ++close ++rows=10 bash --rcfile ".s:bashrc."<CR>"
+execute "noremap <silent><leader>p :botright terminal ++close ++rows=10 ".s:python."<CR>"
 map <C-n> :NERDTreeToggle<CR>
 map <C-p> :FZF<CR>
 
@@ -126,3 +133,130 @@ endif
 "----------- On Startup -----------
 "autocmd StdinReadPre * let s:std_in=1
 "autocmd VimEnter * if argc() == 0 && !exists("s:std_in") | NERDTree | endif
+"
+"
+"----------- CoC vim Configs ----------
+"
+let g:coc_global_extensions = ['coc-tsserver', 'coc-json', 'coc-java', 'coc-python', 'coc-clangd']
+set hidden
+set updatetime=300
+set shortmess+=c
+set signcolumn=number
+
+"--- use <TAB> to trigger completion
+inoremap <silent><expr> <TAB>
+      \ pumvisible() ? "\<C-n>" :
+      \ <SID>check_back_space() ? "\<TAB>" :
+      \ coc#refresh()
+inoremap <expr><S-TAB> pumvisible() ? "\<C-p>" : "\<C-h>"
+" 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
+" Use `:CocDiagnostics` to get all diagnostics of current buffer in location list.
+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 buffer.
+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 for CoCList
+" Show all diagnostics.
+nnoremap <silent><nowait> <space>a  :<C-u>CocList diagnostics<cr>
+" Manage extensions.
+nnoremap <silent><nowait> <space>e  :<C-u>CocList extensions<cr>
+" Show commands.
+nnoremap <silent><nowait> <space>c  :<C-u>CocList commands<cr>
+" Find symbol of current document.
+nnoremap <silent><nowait> <space>o  :<C-u>CocList outline<cr>
+" Search workspace symbols.
+nnoremap <silent><nowait> <space>s  :<C-u>CocList -I symbols<cr>
+" Do default action for next item.
+nnoremap <silent><nowait> <space>j  :<C-u>CocNext<CR>
+" Do default action for previous item.
+nnoremap <silent><nowait> <space>k  :<C-u>CocPrev<CR>
+" Resume latest coc list.
+nnoremap <silent><nowait> <space>p  :<C-u>CocListResume<CR>
+
+