runtime/syntax/rmd.vim

" markdown Text with R statements
" Language: markdown with R code chunks
" Homepage: https://github.com/jalvesaq/R-Vim-runtime
" Last Change: Sat Feb 06, 2016  06:45AM
"
" CONFIGURATION:
"   To highlight chunk headers as R code, put in your vimrc:
"   let rmd_syn_hl_chunk = 1

if exists("b:current_syntax")
  finish
endif

" load all of pandoc info
runtime syntax/pandoc.vim
if exists("b:current_syntax")
  let rmdIsPandoc = 1
  unlet b:current_syntax
else
  let rmdIsPandoc = 0
  runtime syntax/markdown.vim
  if exists("b:current_syntax")
    unlet b:current_syntax
  endif
endif

" load all of the r syntax highlighting rules into @R
syntax include @R syntax/r.vim
if exists("b:current_syntax")
  unlet b:current_syntax
endif

if exists("g:rmd_syn_hl_chunk")
  " highlight R code inside chunk header
  syntax match rmdChunkDelim "^[ \t]*```{r" contained
  syntax match rmdChunkDelim "}$" contained
else
  syntax match rmdChunkDelim "^[ \t]*```{r.*}$" contained
endif
syntax match rmdChunkDelim "^[ \t]*```$" contained
syntax region rmdChunk start="^[ \t]*``` *{r.*}$" end="^[ \t]*```$" contains=@R,rmdChunkDelim keepend fold

" also match and syntax highlight in-line R code
syntax match rmdEndInline "`" contained
syntax match rmdBeginInline "`r " contained
syntax region rmdrInline start="`r "  end="`" contains=@R,rmdBeginInline,rmdEndInline keepend

" match slidify special marker
syntax match rmdSlidifySpecial "\*\*\*"


if rmdIsPandoc == 0
  syn match rmdBlockQuote /^\s*>.*\n\(.*\n\@<!\n\)*/ skipnl
  " LaTeX
  syntax include @LaTeX syntax/tex.vim
  if exists("b:current_syntax")
    unlet b:current_syntax
  endif
  " Extend cluster
  syn cluster texMathZoneGroup add=rmdrInline
  " Inline
  syntax match rmdLaTeXInlDelim "\$"
  syntax match rmdLaTeXInlDelim "\\\$"
  syn region texMathZoneX	matchgroup=Delimiter start="\$" skip="\\\\\|\\\$"	matchgroup=Delimiter end="\$" end="%stopzone\>"	contains=@texMathZoneGroup
  " Region
  syntax match rmdLaTeXRegDelim "\$\$" contained
  syntax match rmdLaTeXRegDelim "\$\$latex$" contained
  syntax region rmdLaTeXRegion start="^\$\$" skip="\\\$" end="\$\$$" contains=@LaTeX,rmdLaTeXSt,rmdLaTeXRegDelim keepend
  syntax region rmdLaTeXRegion2 start="^\\\[" end="\\\]" contains=@LaTeX,rmdLaTeXSt,rmdLaTeXRegDelim keepend
  hi def link rmdLaTeXSt Statement
  hi def link rmdLaTeXInlDelim Special
  hi def link rmdLaTeXRegDelim Special
endif

setlocal iskeyword=@,48-57,_,.

syn sync match rmdSyncChunk grouphere rmdChunk "^[ \t]*``` *{r"

hi def link rmdChunkDelim Special
hi def link rmdBeginInline Special
hi def link rmdEndInline Special
hi def link rmdBlockQuote Comment
hi def link rmdSlidifySpecial Special

let b:current_syntax = "rmd"

" vim: ts=8 sw=2