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

local citation_id_set = {}

local type = utils.type or type

-- Collect all citation IDs.
function Cite (c)
local cs = c.citations
for i = 1, #cs do
citation_id_set[cs[i].id or cs[i].citationId] = true
end
end

--- Return a list of citation IDs
function citation_ids ()
local citations = {};
for cid, _ in pairs(citation_id_set) do
citations[#citations + 1] = cid
end
return citations
end

--- stringify meta inline elements. Pandoc prior to version 2.8
-- didn't properly tag MetaInline values, so making it necessary to use an
-- auxiliary Span.
local stringifyMetaInlines = function (el)
return el.t
and utils.stringify(el)
or utils.stringify(pandoc.Span(el))
end

function bibdata (bibliography)
function bibname (bibitem)
return type(bibitem) == 'string'
and bibitem:gsub('%.bib$', '')
-- bibitem is assumed to be a list of inlines or MetaInlines element
or stringifyMetaInlines(bibitem):gsub('%.bib$', '')
end

local bibs = (type(bibliography) == 'List' or bibliography.t == 'MetaList')
and List.map(bibliography, bibname)
or {bibname(bibliography)}
return table.concat(bibs, ',')
end

function aux_content(bibliography)
local cites = citation_ids()
table.sort(cites)
local citations = table.concat(cites, ',')
return table.concat(
{
'\\bibstyle{alpha}',
'\\bibdata{' .. bibdata(bibliography) .. '}',
'\\citation{' .. citations .. '}',
'',
},
'\n'
)
end

function write_dummy_aux (bibliography, auxfile)
local filename
if type(auxfile) == 'string' then
filename = auxfile
elseif type(auxfile) == 'table' or type(auxfile) == 'Inlines' then
-- assume list of inlines
filename = utils.stringify(pandoc.Span(auxfile))
else
filename = 'bibexport.aux'
end
local fh = io.open(filename, 'w')
fh:write(aux_content(bibliography))
fh:close()
io.stdout:write('Aux written to ' .. filename .. '\n')
return filename
end

function Pandoc (doc)
local meta = doc.meta
if not meta.bibliography then
return nil
else
-- create a dummy .aux file
local auxfile_name = write_dummy_aux(meta.bibliography, meta.auxfile)
os.execute('bibexport ' .. auxfile_name)
io.stdout:write('Output written to bibexport.bib\n')
return nil
end
end

On Monday, January 30, 2023 at 2:41:35 PM UTC-3 John MacFarlane wrote:

In a Lua filter you could probably just use pandoc.read with the format "bibtex" or "biblatex".

> On Jan 30, 2023, at 9:21 AM, Bastien DUMONT <bastien...-VwIFZPTo/vqsTnJN9+BGXg@public.gmane.org> wrote:
>
> Do you mean a function that parses the .bib file directly? I really think that it would be easier to convert the .bib file to a CSL JSON file and import it via a JSON parser.
>
> Le Monday 30 January 2023 à 08:49:36AM, Bernardo C. D. A. Vasconcelos a écrit :
>> Thanks for the feedback, Bastien!
>> Can you think of a similar example script that contains the function to parse
>> the bib data? I searched for it online to no avail.
>> On Saturday, January 28, 2023 at 7:35:40 PM UTC-3 Bastien Dumont wrote:
>>
>> I think that it would be better to run it before citeproc, since you don't
>> want citeproc output (unless you want to still benefit from the "ibid./
>> cited" feature). Citeproc would not help you so much here because it does
>> not tag the different parts of a formatted citation. On the other hand,
>> parsing the bib file would be rather simple if it is in the CSL JSON
>> format: then you would just have to use one of the JSON modules for Lua to
>> import your bibliographic references into a Lua table. If you use Bib(La)
>> TeX, you can convert a .bib file to a .json with `pandoc -f bibtex (or
>> biblatex) -t csljson myfile.bib -o myfile.json`.
>>
>> Le Saturday 28 January 2023 à 02:07:54PM, Bernardo C. D. A. Vasconcelos a
>> écrit :
>>> An HTML equivalent of these commands was proposed in Github, but there
>> was no
>>> feasible way for it to be implemented as part of Citeproc. I suggested a
>> Lua
>>> filter to achieve this and John said it sounded doable.
>>>
>>> I learned some Lua and experimented, but I didn't come close enough to
>> have
>>> something worth sharing. In short: I imagined something like `[@Ref]
>>> {.citetitle}` and `[@Ref]{.citeauthor}`. So this would imply: parsing the
>> bib
>>> data and saving it to a Lua table (stuck here); filtering spans; checking
>> the
>>> type and performing the replacement (not clear to me either what the
>> correct
>>> way would be to replace the id with the data or if this would have to run
>>> before/after citeproc).
>>>
>>> Any pointers would be much appreciated.
>>>
>>> --
>>> You received this message because you are subscribed to the Google Groups
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>> email
>>> to [1]pandoc-discus...-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org.
>>> To view this discussion on the web visit [2][1]https://groups.google.com/
>> d/msgid/
>>> pandoc-discuss/51e71797-b029-4438-be64-6a8a15dd500an%[2]
>> 40googlegroups.com.
>>>
>>> References:
>>>
>>> [1] mailto:pandoc-discus...-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
>>> [2] [3]https://groups.google.com/d/msgid/pandoc-discuss/
>> 51e71797-b029-4438-be64-6a8a15dd500an%40googlegroups.com?utm_medium=email&
>> utm_source=footer
>>
>>
>> --
>> You received this message because you are subscribed to the Google Groups
>> "pandoc-discuss" group.
>> To unsubscribe from this group and stop receiving emails from it, send an email
>> to [4]pandoc-discus...@googlegroups.com.
>> To view this discussion on the web visit [5]https://groups.google.com/d/msgid/
>> pandoc-discuss/4865a325-42c0-4245-b992-b4fbdeab576en%40googlegroups.com.
>>
>> References:
>>
>> [1] https://groups.google.com/d/msgid/
>> [2] http://40googlegroups.com/
>> [3] https://groups.google.com/d/msgid/pandoc-discuss/51e71797-b029-4438-be64-6a8a15dd500an%40googlegroups.com?utm_medium=email&utm_source=footer
>> [4] mailto:pandoc-discus...-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
>> [5] https://groups.google.com/d/msgid/pandoc-discuss/4865a325-42c0-4245-b992-b4fbdeab576en%40googlegroups.com?utm_medium=email&utm_source=footer
>
> --
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