ENV_CLASSES = { 'intro', 'zitat', 'hinweis' }

local function context(s)
  return pandoc.RawBlock('context', s)
end

local function get_env_class(elem)
if elem.classes then
  for i = 1, #elem.classes do
    for j = 1, #ENV_CLASSES do
      if elem.classes[i] == ENV_CLASSES[j] then return ENV_CLASSES[j] end
  end
end
else
  error('function has_class used on an element of type ' ..
        elem.t .. ' that cannot have classes.')
end
end

function Div(el)
  local env_class = get_env_class(el) -- nil if there is none
  if env_class then -- false if env_class is nil
    return { context('\\startparagraph['.. env_class ..']'), el, context('\\stopparagraph') }
  end
end