nvim: Drop supertab

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>

nvim/.config/nvim/config.vim

@@ -40,11 +40,11 @@ set magic                   " Use 'magic' patterns (extended regular expressions
 set autoread                " Autoload file if it changes on disk
 set termguicolors           " Enable colors for terminal
 set completeopt-=menu
-set completeopt+=menuone    " Show the completions UI even with only 1 item
 set completeopt-=longest    " Don't insert the longest common text
 set completeopt-=preview    " Hide the documentation preview window
+set completeopt+=menuone    " Show the completions UI even with only 1 item
 set completeopt+=noinsert   " Don't insert text automatically
-set completeopt-=noselect   " Highlight the first completion automatically
+set completeopt+=noselect   " Do not select a match in the menu
 " Required for vim-workspace
 " See https://github.com/thaerkh/vim-workspace/issues/11
 set sessionoptions-=blank

nvim/.config/nvim/init.vim

@@ -1,7 +1,5 @@
 call plug#begin('~/.config/nvim/plugged')
 
-" Tab completion
-Plug 'ervandew/supertab'
 " Motions
 Plug 'haya14busa/incsearch.vim'
 Plug 'justinmk/vim-sneak'

nvim/.config/nvim/keymappings.vim

@@ -145,6 +145,17 @@ nnoremap <BS> <C-^>
 imap <C-j> <cmd>lua require'source'.prevCompletion()<CR>
 imap <C-k> <cmd>lua require'source'.nextCompletion()<CR>
 
+" Tab completion. Taken from nvim-completion README.
+function! s:check_back_space() abort
+  let col = col('.') - 1
+  return !col || getline('.')[col - 1] =~ '\s'
+endfunction
+
+inoremap <silent><expr> <TAB>
+  \ pumvisible() ? "\<C-n>" :
+  \ <SID>check_back_space() ? "\<TAB>" :
+  \ completion#trigger_completion()
+
 " Asynchronous make
 command! -bang -nargs=* -complete=file Make call asyncdo#run(<bang>0, &makeprg, <f-args>)
 command! -bang -nargs=* -complete=file LMake call asyncdo#lrun(<bang>0, &makeprg, <f-args>)

nvim/.config/nvim/plugin_settings.vim

@@ -12,8 +12,6 @@ let g:gitgutter_sign_modified_removed = 'mr'
 
 " Automatically detect style file and apply style to formatting
 let g:clang_format#detect_style_file = 1
-" Fix tab behaviour while switching through completion options
-let g:SuperTabDefaultCompletionType = "<c-n>"
 " For workspace
 let g:workspace_session_directory = $HOME . '/.vim/session/'
 let g:workspace_undodir = $HOME . '/.vim/undodir'