[nvim] Add rmarkdown, pandoc plugins and bindings

PDFs can be compiled using rmarkdown by invoking <leader>c, or C to open
the file (which pauses vim however). The best workflow is to open the
pdf manually in something like zathura, which will auto-update when the
document is newly compiled.

.config/nvim/init.vim

@@ -85,6 +85,11 @@ Plug 'junegunn/goyo.vim', { 'for': ['markdown', 'txt'], 'on': 'Goyo' } " provide
 Plug 'junegunn/limelight.vim', { 'for': ['markdown', 'txt'], 'on': 'Goyo' } " provide even distraction free-er writing (lowlight paragraphs)
 Plug 'rhysd/vim-grammarous', { 'for': ['markdown', 'txt'], 'on': 'Goyo' } " integrate vim with languagetool for grammar checking (needs java8)
 
+" RMarkdown & LaTeX workflow
+Plug 'vim-pandoc/vim-pandoc-syntax'
+Plug 'vim-pandoc/vim-pandoc'
+Plug 'vim-pandoc/vim-rmarkdown'
+
 " Note-Taking Workflow
 Plug 'lervag/wiki.vim'
 
@@ -142,8 +147,11 @@ augroup END
 au! BufRead,BufNewFile *.markdown set filetype=markdown
 au! BufRead,BufNewFile *.md       set filetype=markdown
 au! BufRead,BufNewFile *.mkd      set filetype=markdown
+au! BufRead,BufNewFile *.rmd      set filetype=markdown
+au! BufRead,BufNewFile *.Rmd      set filetype=markdown
 " automatically enables markdown plugins for md & txt files
 function! Prose()
+  call plug#load('vim-pencil')
   call pencil#init()
   " PLUGIN: vim-textobj-sentence
   " enable extended sentence textobject use on md and plaintext files
@@ -155,10 +163,25 @@ endfunction
 let g:markdown_fenced_languages = ['html', 'python', 'bash=sh', 'javascipt', 'go']
 
 " call the prose function defined above for any md files
-autocmd FileType markdown,txt  call Prose()
+autocmd FileType markdown,txt,rmarkdown  call Prose()
 " or invoke it manually by writing :Prose
 command! -nargs=0 Prose call Prose()
 
+" PLUGIN: vim-pandoc
+let g:pandoc#modules#enabled=["metadata", "toc", "hypertext", "command"]
+let g:pandoc#command#prefer_pdf=1
+let g:pandoc#biblio#bibs=["~/Nextcloud/Library/academia/academia.bib"]
+let g:pandoc#completion#bib#mode='citeproc'
+let g:pandoc#keyboard#use_default_mappings=0
+let g:pandoc#folding#level=2
+let g:pandoc#folding#fold_yaml=1
+let g:pandoc#folding#fastfolds=1
+let g:pandoc#spell#default_langs=["en_us", "de_de"]
+let g:pandoc#hypertext#ausosave_on_edit_open_link=1
+let g:pandoc#hypertext#create_if_no_alternates_exists=1
+" configuration for vim-pandoc and vim-rmarkdown
+let g:pandoc#syntax#conceal#use = 0
+
 " PLUGIN: wiki.vim
 if $WIKIROOT ==? ""
   let g:wiki_root = '~/Nextcloud/Notes/'
@@ -569,6 +592,14 @@ let g:nv_fzf_binds = [
       \ 'ctrl-w:backward-kill-word',
       \ ]
 
+" Markdown & Pandoc compilation group
+" the commented out command can be used if vim-rmarkdown plugin is not
+" installed (it is a bit more brittle)
+" autocmd FileType rmd noremap <F10> :!echo<space>"require(rmarkdown);<space>render('<c-r>%')"<space>\|<space>R<space>--vanilla<enter>
+" Compile with rmarkdown
+autocmd FileType markdown noremap <leader>c :RMarkdown pdf<cr>
+autocmd FileType markdown noremap <leader>C :RMarkdown! pdf<cr>
+
 function! SearchWiki()
   let l:curpath=getcwd()
   :execute(":cd " . g:wiki_root)