Hi group,

I am writing a multilingual document and I want to convert a markdown header to a latex command like so:

## A header | 中文标题

->

\bisection{A header}{中文标题}

Using this example about man pages from the documentation, I have come up with something like the following filter:

~~~lua

local text = pandoc.text
local raw = function (content)
  return pandoc.RawInline('latex', content)
end

function Header(el)
  local pattern = "(%a+)%s+|%s+(.*)"
  headertext = table.unpack(el.content).text
  local _, _, enh, zhh = string.find(headertext, pattern)
  return raw('\\bisection{'..enh..'}{'..zhh..'}')

end

~~~

However, Lua tells me I'm trying to concatenate a nil value `zhh`. I guess it could be that my regex is wrong, or that I'm using string.find incorrectly; I copied the pattern from the Lua manual Section 20.3, "Captures". Can anyone give me any pointers?

Thank you all!

Randy