Error compiling example.tex in TeX4ht

[amarcu5]

Describe the bug Compiling example.tex in TeX4ht fails and produces the following error:

! Undefined control sequence.
<argument> ...y@tempb {cite.ITEM-1\@extra@b@citeb 
                                                  }\ifx \Hy@tempa \ltx@empty...
l.23 \cite{ITEM-1}
                  
? 
! Emergency stop.
<argument> ...y@tempb {cite.ITEM-1\@extra@b@citeb 
                                                  }\ifx \Hy@tempa \ltx@empty...
l.23 \cite{ITEM-1}

Additional information

• TeX distribution: TeX Live 2023
• Package citation-style-language version: 0.4.2
• LaTeX engine: htlatex

To Reproduce

If you have a full texlive installation, compile example.tex with the commands:

pdflatex example
citeproc-lua example
make4ht -a debug example

Alternatively, if you have docker installed:

docker run \
  --rm \
  texlive/texlive \
  /bin/sh -c '
    git clone https://github.com/zepinglee/citeproc-lua.git && \
    cd citeproc-lua/examples && \
    pdflatex example && \
    citeproc-lua example && \
    make4ht -a debug example \
  '

[zepinglee]

Yes, I can reproduce the error.

I'm not familiar with tex4ht. The \@extra@b@citeb is provided in the hyperref package but tex4ht doesn't seem to read it. It still produces another undefined command error (\@skiphyperreftrue) after I patch \providecommand\@extra@b@citeb.

I just find the documentation https://www.kodymirus.cz/tex4ht-doc/ForDevelopers.html but it's not trivial to provide support for tex4t. It should take time to resolve this.

[michal-h21]

I've created a basic configuration file for citeproc-lua, citation-style-language.4ht

% fix problems with \bibitem in the bibliography
\def\setb:anc#1{\def\bib:anc{\def\bib:anc{#1}\ifx \bib:anc\empty \else
      \a:bibitem{}{\a:bibanchor#1}\b:bibitem\fi \gdef\bib:anc{}}%
 \def\AnchorLabel{\bib:anc}
}


\ExplSyntaxOn
% add links to bibliography around citations
\cs_set:Npn \__csl_print_citation:N #1
  {
    \bool_if:NT \l__csl_regression_test_bool
      { \tl_show:N #1 }
    \bool_if:NTF \l__csl_note_bool
      { \footnote {\a:cite\cIteLink{X\l__csl_cite_keys_tl}{bk-\l__csl_citation_id_tl}#1\EndcIteLink\b:cite} }
      {\a:cite\cIteLink{X\l__csl_cite_keys_tl}{bk-\l__csl_citation_id_tl}#1\EndcIteLink\b:cite}
  }
\ExplSyntaxOff

\Hinput{citation-style-language}
\endinput

It resuses the default bibliography support in TeX4ht and fixes two things: the compilation error reported in this bug report, and it also inserts links pointing to the bibliography around citations.