nvim: Switch to nvim-lsp

Enabled lsp within nvim and switched completion engine from deoplete to
completion-nvim.

The completion will be somewhat more barebones for some filetypes until
the language servers are set up, but should then (theoretically) carry a
lot more features than before.

Additionally, we can, over time, add additional code inspection
functionality.

One change concerns the calling of bibtex cite key completion in pandoc
files: Where before the completion would automatically begin after
typing an '@', it will now only start on manual completion invocation
(c-p/c-n) -- since the completion from my current bibtex file takes a
while to load.

nvim/.config/nvim/init.vim

@@ -29,13 +29,13 @@ autocmd VimEnter *
 " defines plugin directory
 " Install plugins from vim with :PlugInstall
 silent! if plug#begin('~/.local/share/nvim/plugged')
-
                                                                                       " base
-Plug 'christoomey/vim-tmux-navigator'
-Plug 'jeffkreeftmeijer/vim-numbertoggle'
-Plug 'justinmk/vim-sneak'
-Plug 'RRethy/vim-illuminate'
+Plug 'christoomey/vim-tmux-navigator'                                                 " allow seamless navigation between vim buffers and tmux splits
+Plug 'jeffkreeftmeijer/vim-numbertoggle'                                              " toggles numbers to absolute for all buffers but the current which is relative
+Plug 'justinmk/vim-sneak'                                                             " jump between letters with improved fFtT quicksearch
+Plug 'RRethy/vim-illuminate'                                                          " highlight other occurences of the word under cursor
 
+                                                                                      " filedrawer
 Plug 'scrooloose/nerdtree', { 'on': ['NERDTreeToggle', 'NERDTreeFind'] }              " show a directory listing within vim
 Plug 'Xuyuanp/nerdtree-git-plugin', { 'on': ['NERDTreeToggle', 'NERDTreeFind'] }      " show git status in nerdtree for files and dirs
 
@@ -51,11 +51,8 @@ Plug 'junegunn/vim-peekaboo' " Show the contents of regiseters on pasting from '
 Plug 'junegunn/fzf', { 'dir': '~/.fzf', 'do': './install --bin' }
 Plug 'junegunn/fzf.vim'
 
-" ultimately the only thing left here should be a
-Plug 'Shougo/deoplete.nvim' " automatic suggestions, can also perhaps be changed for newer plugs
-Plug 'deoplete-plugins/deoplete-go', { 'do': 'make'}
-Plug 'deoplete-plugins/deoplete-jedi'
-Plug 'Shougo/echodoc.vim', {}
+Plug 'neovim/nvim-lspconfig'                                                          " some commong language server configurations
+Plug 'nvim-lua/completion-nvim'                                                       " simple completion engine built specifically for nvim and lsp
 Plug 'desmap/ale-sensible' | Plug 'w0rp/ale'                                          " asynchronous linting - might be superseded by lsp or coc.nvim at some point
                                                                                       " statusline
 Plug 'vim-airline/vim-airline'
@@ -69,15 +66,16 @@ Plug 'reedes/vim-colors-pencil'
 Plug 'vim-pandoc/vim-pandoc-syntax'
 Plug 'vim-pandoc/vim-pandoc'
                                                                                       " Notes and Wiki
-Plug 'dyng/ctrlsf.vim'
-Plug 'lervag/wiki.vim'
-Plug 'alok/notational-fzf-vim'
+Plug 'dyng/ctrlsf.vim'                                                                " search-and-edit of many wiki files at once
+Plug 'lervag/wiki.vim'                                                                " foundational wiki system, allowing links between plaintext files
+Plug 'alok/notational-fzf-vim'                                                        " quickly search through the wiki
                                                                                       " Prose Workflow
 Plug 'micarmst/vim-spellsync'                                                         " personal dict improvements for git sync
 Plug 'ron89/thesaurus_query.vim'                                                      " find thesaurus backed synonyms for word under cursor
 Plug 'kana/vim-textobj-user'                                                          " dependency for most other textobj plugins
 Plug 'reedes/vim-textobj-sentence'                                                    " extends the capabilities of sentence detection
                                                                                       " and allows you to jump to the *end* of this <g)> or last <g(> sentence.
+
 Plug 'reedes/vim-pencil', { 'for': ['pandoc', 'markdown', 'txt'], 'on': 'Goyo' }      " provide md convenience functions like hard/softwrap
 Plug 'junegunn/goyo.vim', { 'for': ['pandoc', 'markdown', 'txt'], 'on': 'Goyo' }      " provide distraction free writing
 Plug 'junegunn/limelight.vim', { 'for': ['pandoc', 'markdown', 'txt'], 'on': 'Goyo' } " provide even distraction free-er writing (lowlight paragraphs)

nvim/.config/nvim/lua/pandoc_complete.lua

@@ -0,0 +1,13 @@
+local M = {}
+
+function M.getCompletionItems(prefix)
+  -- define your total completion items
+  local items = vim.api.nvim_call_function('pandoc#completion#Complete',{0, prefix})
+  return items
+end
+
+M.complete_item = {
+  item = M.getCompletionItems
+}
+
+return M

nvim/.config/nvim/plugin/completion-nvim.vim

@@ -0,0 +1,59 @@
+" use completion-nvim for all buffers (not just lsp)
+autocmd BufEnter * lua require'completion'.on_attach()
+
+"map <c-p> to manually trigger completion
+imap <silent> <c-p> <Plug>(completion_trigger)
+imap <silent> <c-n> <Plug>(completion_trigger)
+
+" Add <Tab> and <S-Tab> to navigate through popup menu
+inoremap <expr> <Tab>   pumvisible() ? "\<C-n>" : "\<Tab>"
+inoremap <expr> <S-Tab> pumvisible() ? "\<C-p>" : "\<S-Tab>"
+
+
+" Set completeopt to have a better completion experience
+set completeopt=menuone,noinsert,noselect
+
+" Avoid showing message extra message when using completion
+set shortmess+=c
+
+" set loop of strategies in descending order
+let g:completion_matching_strategy_list = ['exact', 'substring', 'fuzzy']
+
+" even when backtracking enable completion
+let g:completion_trigger_on_delete = 1
+
+" register new completion engines
+" (set in rtp/lua/*_complete.lua)
+"
+" pandoc citation key completion
+lua require'completion'.addCompletionSource('bibcite', require'pandoc_complete'.complete_item)
+
+" only call for specified shortcut, or with completion keys
+augroup pandocCompletion
+    autocmd!
+    autocmd BufEnter * call SetupPandocCompletion()
+augroup end
+fun! SetupPandocCompletion()
+    if &ft =~ 'pandoc'
+        let g:completion_enable_auto_popup = 0
+        let g:completion_trigger_character = ['@\w*']
+        return
+    endif
+    let g:completion_enable_auto_popup = 1
+    let g:completion_trigger_character = ['.']
+endfun
+
+" the completion chains for different filetypes
+" see https://github.com/nvim-lua/completion-nvim/wiki/chain-complete-support
+let g:completion_chain_complete_list = {
+    \ 'pandoc': [
+    \    {'complete_items': ['bibcite', 'lsp', 'snippet']},
+    \    {'mode': '<c-p>'},
+    \    {'mode': '<c-n>'}
+    \],
+    \ 'default': [
+    \    {'complete_items': ['lsp', 'snippet']},
+    \    {'mode': '<c-p>'},
+    \    {'mode': '<c-n>'}
+    \]
+\}

nvim/.config/nvim/plugin/deoplete.vim

@@ -1,20 +0,0 @@
-" PLUGIN: DEOPLETE
-" For async completion
-" enable deoplete at startup
-let g:deoplete#enable_at_startup =1
-
-call deoplete#custom#option( {
-      \ 'camel_case': v:true,
-      \ 'smart_case': v:true,
-      \ 'ignore_case': v:true,
-      \ 'refresh_always': v:true,
-      \ 'max_abbr_width': 0,
-      \ 'max_menu_width': 0
-      \} )
-
-call deoplete#custom#var('omni', 'input_patterns', {
-      \'pandoc': '@\w*',
-      \})
-call deoplete#custom#var('omni', 'functions', {
-      \'pandoc': 'pandoc#completion#Complete',
-      \})

nvim/.config/nvim/plugin/echodoc.vim

@@ -1,7 +0,0 @@
-" PLUGIN: ECHODOC
-let g:echodoc#type="virtual"
-let g:echodoc_enable_at_startup=1
-set splitbelow
-set completeopt+=menu,menuone,noinsert,noselect
-set completeopt-=preview
-autocmd CompleteDone * pclose

nvim/.config/nvim/plugin/nvim-lspconfig.vim

@@ -0,0 +1,4 @@
+
+" enable python language servers
+lua require'nvim_lsp'.pyls.setup{}
+lua require'nvim_lsp'.vimls.setup{}

nvim/.config/nvim/plugin/vim-polyglot.vim

@@ -1,7 +1,7 @@
 " PLUGIN: vim-polyglot
 "
 " we disable markdown so that every markdown file can be given pandoc type
-let g:polyglot_disabled = ['markdown']
+" let g:polyglot_disabled = ['markdown']
 
 au BufNewFile,BufRead *.{md,mdown,mkd,mkdn,markdown,mdwn} set ft=pandoc
 au BufNewFile,BufRead *.{md,mdown,mkd,mkdn,markdown,mdwn}.{des3,des,bf,bfa,aes,idea,cast,rc2,rc4,rc5,desx} set ft=pandoc