How to add a alphabetical index with Pandoc?

Question

I have a markdown file and I want to PDF with a last section with alphabetical index such as latex alphabetical index.

But I have been looking in the pandoc manual and looking for a Lua plugin for this thing, but I have not seen anything.

Answer 1

You could use a filter. Assuming that you enclose your indexed words with a span id="index" and that you have a div id='compiled_index where you want the index to show, the following should do what you want.

function buildMap(dic, idx)
    table.sort(idx)
    for i,v in ipairs(idx) do
        local key = string.upper(string.sub(v, 1, 1))
        if(dic[key] == nil) then
            dic[key] = {pandoc.Para(pandoc.Link(v,"#"..v))}
        else 
            table.insert(dic[key],pandoc.Para(pandoc.Link(v,"#"..v)))
        end
    end
    return dic
end

function Span(el)
    if el.identifier == 'index' then
    local index = pandoc.utils.stringify(el.content) 
        table.insert(idx,index)
    out = pandoc.Link(index,"")
    out.identifier=index
  return out
  end
end

function Div(el)
    if el.identifier == 'compiled_index' then
    local list = buildMap(dic,idx)
    local lists = {}
    for key, items in pairs(list) do
        local inner_list = {}
        for _,item in pairs(items) do
          table.insert(inner_list,item)
        end
        table.insert(lists,pandoc.DefinitionList{{key, inner_list}})
    end
    return lists
  end
end

You can then run pandoc -L <filterName>.lua -t html <inputFile>.md -o <outputFile>.html