How to display one bibliography in different styles according to the language which is used in the references using CSL and citeproc? - pandoc

Question

I would like to ask a question related to an ongoing issue in the GitHub repository of jgm/citeproc here, since my question may come to be out of scope of the original issue.
I'm trying to apply an approach proposed in a comment on the thread on GitHub to a csl file so that I can display English references and non-English ones (Chinese lang-zh, here) in different layouts according to their language. That is, when citeproc finds that a bib entry of a .bib file contains a csl's variable (say lang-zh), that bib entry is displayed in a layout that is specified in the csl's if-statement as shown below:
<citation>
...
<layout>
<choose>
<if variable="lang-zh">
<!--
Multibyte comma as a deliminater for non-English references
-->
<group delimiter="，">
<text macro="author-short-zh" />
<text macro="issued-year-zh" />
<text macro="citation-locator-zh" />
</group>
</if>
<else>
<!--
Normal comma as a deliminater for references in the default language (English)
-->
<group delimiter=", ">
<text macro="author-short" />
<text macro="issued-year" />
<text macro="citation-locator" />
</group>
</else>
</choose>
</layout>
</citation>
However, the variable/tag lang-zh in the .bib file seems to be ignored even when I add such filed as lang-zh = {yes}, variable = {lang-zh}, or language = {lang-zh} to the .bib file, as shown below.
#article{chen2012,
title = {基于电无级变速器的内燃机最优控制策略及整车能量管理},
author = {陈骁 and 黄声华 and 万山明 and 庞珽},
journal = {电工技术学报},
volume = {27},
number = {2},
pages = {133--138},
year = {2012},
lang-zh = {yes},
variable = {lang-zh},
language = {lang-zh}
}
Then how should I add a filed or variable to the .bib file that can be recognised by the csl?
(M)WE
Full .csl file (say mod_apa_zh_pulipuli.csl)
You can find the .csl file from https://github.com/jgm/citeproc/issues/120#issuecomment-1296207148
(Its original csl called apa_zh_pulipuli.csl is from https://raw.githubusercontent.com/pulipulichen/blogger/master/project/zotero/apa_zh_pulipuli.csl)
tests.bib
#book{xie2015,
title = {Dynamic Documents with {R} and knitr},
author = {Yihui Xie},
publisher = {Chapman and Hall/CRC},
address = {Boca Raton, Florida},
year = {2015},
edition = {2nd},
note = {ISBN 978-1498716963},
url = {http://yihui.name/knitr/},
language = {English}
}
#article{chen2012,
title = {基于电无级变速器的内燃机最优控制策略及整车能量管理},
author = {陈骁 and 黄声华 and 万山明 and 庞珽},
journal = {电工技术学报},
volume = {27},
number = {2},
pages = {133--138},
year = {2012},
lang-zh = {yes},
variable = {lang-zh},
language = {lang-zh}
}
test.md
---
bibliography: [test.bib]
csl: mod_apa_zh_pulipuli.csl
---
#xie2015
#chen2012

Answer 1

As #adam.smith suggested here, using a CSL JSON (.json) file as a bibliography source does the trick:
Convert a .bib file to a CSL JSON (.json) file via pandoc by pandoc .\tests.bib -t csljson -o tests.json (see also an answer in TeX.SE);
Add "lang-zh": "yes" to the generated .json file (This process is mandatory since such a non-standard field as lang-zh = {yes} in .bib is not transferred to a CSL JSON);
Change the bibliography field in the YAML of .md file so that pandoc can refer to the .json file
MWE
test.json
[
{
"URL": "http://yihui.name/knitr/",
"author": [
{
"family": "Xie",
"given": "Yihui"
}
],
"edition": "2nd",
"id": "xie2015",
"issued": {
"date-parts": [
[
2015
]
]
},
"note": "ISBN 978-1498716963",
"publisher": "Chapman; Hall/CRC",
"publisher-place": "Boca Raton, Florida",
"title": "Dynamic Documents with R and knitr",
"type": "book"
},
{
"author": [
{
"family": "陈骁"
},
{
"family": "黄声华"
},
{
"family": "万山明"
},
{
"family": "庞珽"
}
],
"container-title": "电工技术学报",
"id": "chen2012",
"issue": "2",
"issued": {
"date-parts": [
[
2012
]
]
},
"page": "133-138",
"title": "基于电无级变速器的内燃机最优控制策略及整车能量管理",
"type": "article-journal",
"volume": "27",
"lang-zh": "yes"
}
]
test.md
---
bibliography: [test.bib]
csl: mod_apa_zh_pulipuli.csl
---
#xie2015
#chen2012