CodeBlock: (block) ->
  { label } = block.classes
  cmd = "pygmentize -f html -O style=dracula,wrapcode,classprefix=py- -l %s %s"
  fname = os.tmpname!

  with io.open fname, "w"
    \write block.text
    \close!

  switch label
    when "moon", "moonscript"
      p = io.popen (cmd .. " -x")\format "moonscript.py", fname
      out = with p\read"*a"
        p\close!
      -- syntax highlight with pygments
      pandoc.RawBlock "html", out
    else
      status, handle = pcall -> io.popen cmd\format label or "text", fname
      out = handle\read"*a"

      if out\len! == 0
        -- syntax highlight with pandoc
        block
      else
        -- syntax highlight with pygments
        pandoc.RawBlock "html", out