filter to get url from citeproc pandoc

filters.lua

local List = require 'pandoc.List'
local utils = require 'pandoc.utils'
local stringify = utils.stringify
local run_json_filter = utils.run_json_filter

local pretty_dump = require"pl.pretty".dump

function isItALink (spc)
  return spc and spc.t == 'Link'
end


function read_inline (inlines)
  for i = #inlines-1,1,-1 do
    if isItALink(inlines[i]) then
      print(stringify(inlines[i]))
    end
  end
  return inlines
end

function modify_doc_citation(doc)

    for i,el in pairs(doc.blocks) do
        
        if (el.t == "Div") then
          if el.identifier:match('^refs([_%w]*)$') then
           	--pretty_dump(el.identifier)
           pandoc.walk_block(el, { Inlines = function (e) read_inline(e) end})
          end
        end
    end
    
    return doc
end

function Inlines (inlines)
  
  for i = #inlines-1,1,-1 do
      print(pandoc.utils.stringify(inlines[i]))
  end
  return inlines
end

local function run_citeproc(doc, quiet)
  if PANDOC_VERSION >= "2.11" then
    return run_json_filter(
      doc,
      'pandoc',
      {'--from=json', '--to=json', '--citeproc', quiet and '--quiet' or nil}
    )
  else
    -- doc = run_json_filter(doc, 'pandoc-citeproc')
    return run_json_filter(
      doc,
      'pandoc-citeproc',
      {FORMAT, (quiet and supports_quiet_flag) and '-q' or nil}
    )
  end
end

local function resolve_doc_citations (doc)
  doc = run_citeproc(doc)
  return doc
end

return {
   { Pandoc = resolve_doc_citations },
   {Pandoc = modify_doc_citation}
  }

gistfile1.txt

pandoc --lua-filter=filter.lua -f markdown -t json --citeproc -o test.json test.md
> https://duckduckgo.com/cite2020
> https://duckduckgo.com/cite2021

test.bib

@book{cite2020,
	title = {Title},
	author = {Author},
	year = {2020},
	url = {https://duckduckgo.com/cite2020}
}

@book{cite2021,
	title = {Title},
	author = {Author2},
	year = {2021},
	url = {https://duckduckgo.com/cite2021}
}

test.md

bibliography	biblio-style	link-citations
test.bib	apalike	true

Section One

Hello world, citing [@cite2020] and [@cite2021] !

This i the last line