Etoolbox error with make4ht

etoolboxmake4httex4ht

The following example, despite a the generated HTML seems okay, shows an error message.

Example file:

\documentclass{article}

\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@incollection{lin_impressions_1936,
  address = {Berkeley},
  title = {Impressions on {Reaching} {America}},
  booktitle = {Land without {Ghosts}: {Chinese} {Impressions} of {America} from the {MidNineteenth} {Century} to the {Present}},
  publisher = {University of California Press},
  author = {Lin, Y. T.},
  editor = {Arkush, R. D. and Lee, L. O.},
  year = {1936},
  pages = {160--63},
}
\end{filecontents}

\usepackage[backend=biber]{biblatex}
\addbibresource{\jobname.bib}

\begin{document}
Lorem ipsum~\cite{lin_impressions_1936}.
Dolor sit amet~\textcite{lin_impressions_1936}.

\printbibliography
\end{document}

Compiled with:

make4ht -x -u article

Generated HTML:

enter image description here

Error message:

[ERROR]   htlatex: Compilation errors in the htlatex run
[ERROR]   htlatex: Filename     Line    Message
[ERROR]   htlatex: ./article.aux        10       Package etoolbox Error: Boolean '\ifrefcontextdefaults' undefined.
[ERROR]   htlatex: ./article.aux        12       Package etoolbox Error: Boolean '\ifrefcontextdefaults' undefined.

Content of .log file:

! Package etoolbox Error: Boolean '\ifrefcontextdefaults' undefined.

See the etoolbox package documentation for explanation.
Type  H <return>  for immediate help.
 ...

l.12 ...pressions_1936}{nty/global//global/global}

Your command was ignored.

Best Answer

It seems that this is an error in biblatex.4ht which happens only in the XeTeX mode. This is the culprit:

\ifdefined\XeTeXversion
  \def\abx@aux@defaultrefcontext#1#2#3{%
  \global\boolfalse{refcontextdefaults}%
  \csxdef{blx@assignedrefcontextbib@#1@\detokenize{#2}}{\detokenize{#3}}}
\fi

It redefines some internal macro when XeTeX is active, adding additional \detokenize to protect special characters. It seems that the refcontextdefaults boolean variable is not used by BibLaTeX anymore, so we can just remove this line. It seems to fix the issue.

Here is the full biblatex.4ht with the fix:

% biblatex.4ht (2021-12-27-13:23), generated from tex4ht-4ht.tex
% Copyright 2007-2009 Eitan M. Gurari
% Copyright 2009-2021 TeX Users Group
%
% This work may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either
% version 1.3c of this license or (at your option) any
% later version. The latest version of this license is in
%   http://www.latex-project.org/lppl.txt
% and version 1.3c or later is part of all distributions
% of LaTeX version 2005/12/01 or later.
%
% This work has the LPPL maintenance status "maintained".
%
% The Current Maintainer of this work
% is the TeX4ht Project <http://tug.org/tex4ht>.
%
% If you modify this program, changing the
% version identification would be appreciated.
\immediate\write-1{version 2021-12-27-13:23}

   \def\make:blx:ver#1.#2#3\relax{%
   %\ifdim#1pt< 3pt \xdef\blx:ver:no{2}\else\xdef\blx:ver:no{3}\fi%
   \gdef\blx:ver:no{#1}
   \gdef\blx:subver:no{#2}
}
\expandafter\make:blx:ver\[email protected]\relax
\ifx\a:printshorthands\Undef\let\blx@shorthands\@empty\fi
\ifx\blx@startbib\:UnDef
 \pend:def\blx@shorthands{%
   \pend:def\blx@bibinit{%
       \HAssign\shorthands:cnt=0
       \NewConfigure{printfield-shorthand}{2}%
       \Configure{printfield-shorthand}%
         {\gHAdvance\shorthands:cnt by 1\relax
          \ifnum \shorthands:cnt=1 \a:printshorthands
          \else                    \c:printshorthands \fi
         }
         {\d:printshorthands}%
   \append:def\endtheshorthands{\b:printshorthands}%
   \csname a:@shorthands\endcsname}
}
\ifx\b:printshorthands\Undef\let\endtheshorthands\@empty\fi
\def\a:entryhead{CVR}
\def\a:entryhead:full{CV Radhakrishnan}
\ifx\bib@macro@entryhead:name\UnDef
  \let\bib@macro@entryhead:name\@empty\fi
\ifx\bib@macro@entryhead:full\UnDef
  \let\bib@macro@entryhead:full\@empty\fi
  \gdef\BibFileName[#1]#2{\expandafter\xdef\csname
       BibFileName#1\endcsname{#2}}
\newcount\sv:sec:cnt
\def\bibSecConfigure{%
  \let\save:section\section
  \global\sv:sec:cnt=\c@secnumdepth
  \def\section{\@ifstar
      {\c@secnumdepth=0\relax\save:section}%
      {\c@secnumdepth=\sv:sec:cnt\save:section}}%
}
\gHAssign\bibN=0
\ifdefined\TE@hook\else%
\def\TE@hook{}%
\fi%

\AtBeginDocument{%
  \Configure{ifthenelse}{\TE@hook}
}
  \:CheckOption{ooffice}\if:Option
   \def\bibConfigure{\ConfigureList{thebibliography}%
      {\IgnorePar\EndP \gHAdvance\bib:N by 1
       \HCode{<text:bibliography text:name="bib-\bib:N" >
              <text:bibliography-source>\Hnewline
             <text:index-title-template>}
           \NoFonts\ref:name\EndNoFonts
       \HCode{</text:index-title-template>\Hnewline
%
           <text:bibliography-entry-template\Hnewline
            text:bibliography-type="custom1"
            text:style-name="Bibliography11">\Hnewline
%
            <text:index-entry-bibliography
             text:bibliography-data-field="identifier"/>\Hnewline
%
           <text:index-entry-span>: </text:index-entry-span>\Hnewline
           <text:index-entry-bibliography
            text:bibliography-data-field="author" />\Hnewline
           <text:index-entry-span>, </text:index-entry-span>\Hnewline
%
           <text:index-entry-bibliography
            text:bibliography-data-field="title" />\Hnewline
           <text:index-entry-span>, </text:index-entry-span>\Hnewline
%
           <text:index-entry-bibliography
            text:bibliography-data-field="year" />\Hnewline
           </text:bibliography-entry-template>\Hnewline\Hnewline
           </text:bibliography-source>\Hnewline
           <text:index-body>\Hnewline}%
         \let\en:bib=\empty
      }%
      {\en:bib\HCode{</text:index-body></text:bibliography>}}
      {\en:bib\gdef\en:bib{\HCode{</text:p>\Hnewline}}%
        \HCode{<text:p text:style-name="p-bibitem">}%
        \gHAdvance\bibN by 1
        \HCode{<text:reference-mark
          text:name="X0-\csname BIB-\bibN\endcsname">%
          </text:reference-mark>}%
      }%
      {}{}
  }

  \else
    \def\bibConfigure{%
  \ConfigureList{thebibliography}
  {\ifvmode \IgnorePar \fi \EndP \EndP
    \HCode {<dl class="thebibliography">}%
%
% This is for linking citations with biblist items which
% are in a different file when output is split into different
% chunks. [CVR 2012-09-27]
%
%
% <biblatex-2.2>
%
  \immediate\write\@auxout{%
      \string\BibFileName[\therefsection]{\FileName}}%
%
% </biblatex-2.2>
%
    \PushMacro \end:itm \global \let \end:itm =\empty}%
  {\ifvmode \IgnorePar \fi \EndP
    \PopMacro \end:itm \global \let \end:itm \end:itm \EndP
    \HCode {</dd></dl>}\ShowPar}%
  {\ifvmode \IgnorePar \fi \EndP \gHAdvance \bibN by 1
    \end:itm \global \def \end:itm {\EndP \Tg </dd>}%
    \HCode {<dt id="X\therefsection-\abx@field@entrykey"
      class="thebibliography">}\bgroup \bf}%
  {\ifvmode \IgnorePar \fi \EndP
    \egroup
    \HCode {</dt><dd\Hnewline id="bib-\bibN"
      class="thebibliography">}%
    \par \ShowPar}%
 }

 \fi
\NewConfigure{printshorthands}{4}
\NewConfigure{@shorthands}[1]{\concat:config\a:@shorthands{#1}}
\let\a:@shorthands\empty
% \def\nolinkurl{\o:url:}
% \def\blx@checksum{\ifx \blx@checksum@old \blx@checksum@new \else
%   \blx@warning@noline {Page references have changed.\MessageBreak
%     Rerun to get references right}\@tempswatrue \blx@reruntrue \fi
%   \@nameuse {blx@rerun}}
\def\blx@checksum#1#2#3{%
  \begingroup
  \blx@tempcnta\the\numexpr0#2*0#3\relax
  \blx@tempcntb\blx@tempcnta
  \divide\blx@tempcntb10
  \multiply\blx@tempcntb10
  \advance\blx@tempcnta-\blx@tempcntb
  \xdef#1{#1\the\blx@tempcnta}%
  \endgroup}

\@ifpackagelater{biblatex}{2018/03/01}{\let\blx:pend:def\pend:defI}{\let\blx:pend:def\pend:def}
\blx:pend:def\blx@bibliography{\bibSecConfigure%
  \pend:def\blx@bibinit{%
    \bibConfigure
     \csname onthebibliography:list\endcsname
  }%
}
\let\en:bib\@empty
\newcounter{bib}
\ifnum\blx:ver:no < 3
 \protected\def\blx@bbl@entry#1#2#3{%
  \begingroup
  \def\texht@bibkey{#1}
  \edef\abx@field@entrykey{\detokenize{#1}}%
  \global\advance\c@bib 1
  \immediate\write\@auxout{\string\expandafter\string\gdef
    \string\csname\space BIB-\thebib\string\endcsname
     {\expandafter\strip@prefix\meaning\texht@bibkey}}%
  \Tag{)QX\therefsection-#1}{\thebib}%
  \blx@setoptions@type{#2}%
  \blx@bbl@options{#3}%
  \blx@setoptions@entry
  \edef\blx@bbl@data{blx@data@\the\c@refsection @\abx@field@entrykey}%
  \csuse\blx@bbl@data
  \cslet\blx@bbl@data\@empty
  \blx@bbl@addfield{entrykey}{\abx@field@entrykey}%
  \blx@bbl@addfield{entrytype}{#2}%
  \blx@imc@iffieldundef{options}
    {}
    {\blx@bbl@fieldedef{options}{\expandonce\abx@field@options}}}
%
 \protected\def\blx@finentry{%
  \unspace
  \a:finentry
      \finentrypunct
      \blx@postpunct
  \b:finentry
  \blx@initunit
 }
%
\else
% Biblatex 3.0
%
% Hacks for biblatex
% MakeUppercase is redefined by tex4ht, biblatex tries to redefine it as well, but it relies on original
% LaTeX version:
\DeclareRobustCommand{\MakeUppercase}[1]{{%
  \def\i{I}\def\j{J}%
  \def\reserved@a##1##2{\let##1##2\reserved@a}%
  \expandafter\reserved@a\@uclclist\reserved@b{\reserved@b\@gobble}%
  \let\UTF@two@octets@noexpand\@empty
  \let\UTF@three@octets@noexpand\@empty
  \let\UTF@four@octets@noexpand\@empty
  \blx@hook@uc\protected@edef\reserved@a{\uppercase{#1}}%
  \reserved@a
}}
% Same applies also for \MakeLowercase
\DeclareRobustCommand{\MakeLowercase}[1]{{%
  \def\reserved@a##1##2{\let##2##1\reserved@a}%
  \expandafter\reserved@a\@uclclist\reserved@b{\reserved@b\@gobble}%
  \let\UTF@two@octets@noexpand\@empty
  \let\UTF@three@octets@noexpand\@empty
  \let\UTF@four@octets@noexpand\@empty
  \blx@hook@lc\protected@edef\reserved@a{\lowercase{#1}}%
  \reserved@a
}}

% I don't really understand this, but language processing is broken by default
% with biblatex. It loads language file, but it executes code which should be
% executed only in the case if the language file fails, it displays an error message
% and language handling doesn't work. When we execute following code, the language
% files are loaded before checking of the success and it seems to work.

\AtBeginDocument{%
\@ifpackageloaded{babel}
      {% This is required for languages which are never explicitly selected
        % It seems this code was executed also with Polyglossia, where it caused compilation error
        \@ifpackageloaded{polyglossia}{}{%
        \def\do#1{\blx@lbxinput{#1}{}{}}%
       \ifx\@empty\bbl@loaded\else%
       \expandafter\docsvlist\expandafter{\bbl@loaded}%
      \fi}}{}%
}
\fi % end of version boolean
\NewConfigure{finentry}{2}
\def\:tempc[#1]#2{%
   \expandafter\ifx \csname a:printfield-#2\endcsname\relax
      \NewConfigure{printfield-#2}{2}%
      \a:printfield{printfield-#2}%
   \fi
   \Configure{blx@unit}%
       {\csname a:printfield-#2\endcsname}%
       {\csname b:printfield-#2\endcsname}%
   \csname o:\string\blx@printfield:\endcsname[#1]{#2}%
}
\expandafter\HLet\csname\string\blx@printfield\endcsname\:tempc
\NewConfigure{printfield}[1]{\def\a:printfield##1{#1}}
\Configure{printfield}{%
    \Configure{#1}%
       {\HCode{<!--#1-->}}%
       {\HCode{<!--/#1-->}}%
}
\def\:tempc[#1]#2{%
   \expandafter\ifx \csname a:bibstring-#2\endcsname\relax
      \NewConfigure{bibstring-#2}{2}%
      \a:printfield{bibstring-#2}%
   \fi
   \Configure{blx@unit}%
       {\csname a:bibstring-#2\endcsname}%
       {\csname b:bibstring-#2\endcsname}%
   \csname o:\string\blx@bibstring:\endcsname[#1]{#2}%
}
\expandafter\HLet\csname\string\blx@bibstring\endcsname\:tempc
\def\:tempc[#1]#2{%
   \expandafter\ifx \csname a:bibcpstring-#2\endcsname\relax
      \NewConfigure{bibcpstring-#2}{2}%
      \a:printfield{bibcpstring-#2}%
   \fi
   \Configure{blx@unit}%
       {\csname a:bibcpstring-#2\endcsname}%
       {\csname b:bibcpstring-#2\endcsname}%
   \csname o:\string\blx@bibcpstring:\endcsname[#1]{#2}%
}
\expandafter\HLet\csname\string\blx@bibcpstring\endcsname\:tempc
\def\:tempc[#1]#2{%
   \expandafter\ifx \csname a:biblcstring-#2\endcsname\relax
      \NewConfigure{biblcstring-#2}{2}%
      \a:printfield{biblcstring-#2}%
   \fi
   \Configure{blx@unit}%
       {\csname a:biblcstring-#2\endcsname}%
       {\csname b:biblcstring-#2\endcsname}%
   \csname o:\string\blx@biblcstring:\endcsname[#1]{#2}%
}
\expandafter\HLet\csname\string\blx@biblcstring\endcsname\:tempc
\def\:tempc[#1]#2{%
   \expandafter\ifx \csname a:bibucstring-#2\endcsname\relax
      \NewConfigure{bibucstring-#2}{2}%
      \a:printfield{bibucstring-#2}%
   \fi
   \Configure{blx@unit}%
       {\csname a:bibucstring-#2\endcsname}%
       {\csname b:bibucstring-#2\endcsname}%
   \csname o:\string\blx@bibucstring:\endcsname[#1]{#2}%
}
\expandafter\HLet\csname\string\blx@bibucstring\endcsname\:tempc
\NewConfigure{biblatex-style}[2]{%
   \def\:temp{#1}%
   \ifx \:temp\blx@cbxfile
      #2%
      \global\let\biblatex:style\def
   \fi
}

\def\biblatex:style{}
\Configure{biblatex-style}{}{}

\pend:def\at:docend{%
   \ifx \UnDef\biblatex:style
      \:warning{\string\Configure{biblatex-style}{\blx@cbxfile}{...}
         not available}%
   \fi
}
\let\blx:item\@item
\def\@item[#1]{%
  \blx:item[#1]%
  \ifhmode \spacefactor\blx@sf@par\fi
}
\let\blx@resetpuncthook\@empty
\let\blx@csq@ifkernmark\@empty
\newskip\blx@unitmark
\blx@unitmark=10pt plus 1pt minus 1pt
\let\abx@aux@page\@gobbletwo
\let\abx@aux@fnpage\@gobbletwo
\let\abx@aux@refsection\@gobbletwo
%
% <[email protected]> reported that After updating
% biblatex and biblatex.ht to versions 2.2 respectively
% 2012-09-28-17:49 (using MiKTeX 2.9 64 bit), tex4ht seemed no longer
% respected the defernumbers option in biblatex.sty: When applied to
% the attached file tex4hterror.tex.
%
% The problem was due to nullifying \abx@aux@number which in fact
% should have been redefined to \blx@aux@number when defernumbers
% option is true.
%
% This is done now and as per Kristian, the fix works fine now.
%
\ifnum\blx:ver:no < 3
%
 \protected\def\blx@aux@number#1#2#3#4{%
  \blx@bbl@addentryfield{\detokenize{#2}}{#3}{localnumber}{#4}%
  \ifblank{#4}%
    {}%
    {\csgdef{blx@labelnumber@#3}{#4}%
     %\blx@addchecksum{#1}{#4} % this can cause a nodocument error!
     }}
%
 \iftoggle{blx@defernumbers}%
    {\setkeys{blx@opt@pre}{labelnumber}%
     \let\blx@thelabelnumber\blx@addlabelnumber
     \let\abx@aux@number\blx@aux@number}%
    {\let\blx@thelabelnumber\relax
     \let\abx@aux@number\@gobblefour}
%
\else
  \def\@gobblefive#1#2#3#4#5{}%
 \protected\def\blx@aux@number#1#2#3#4#5{%
   \blx@bbl@addentryfield{\detokenize{#2}}{#3}{localnumber}{#4}{#5}%
   \blx@bbl@addentryfield{\detokenize{#2}}{#3}{labelnumber}{#4}{#5}%
   \global\toggletrue{blx@localnumber}%
   \ifblank{#5}
    {}
    {\csgdef{blx@labelnumber@#3@#4}{#5}}}

 \iftoggle{blx@defernumbers}%
    {\setkeys{blx@opt@pre}{labelnumber}%
     \let\blx@thelabelnumber\blx@addlabelnumber
     \let\abx@aux@number\blx@aux@number}%
    {\let\blx@thelabelnumber\relax
     \let\abx@aux@number\@gobblefive}
\fi % end of version boolean
%
\AtEndDocument{%
  \def\abx@aux@page#1#2{\blx@addpagesum{#1}{#2}}%
  \def\abx@aux@fnpage#1#2{\blx@addpagesum{#1}{#2}}%
}
%
\def\blx@begunit{%
  \toggletrue{blx@tempa}%
  \iftoggle{blx@insert}%
    {\iftoggle{blx@unit}%
       {\begingroup
          \let\blx@begunit\@empty
          \let\blx@endunit\@empty
          \let\blx@endnounit\@empty
          \blx@unitpunct\blx@postpunct
        \endgroup
        \global\togglefalse{blx@unit}%
        \togglefalse{blx@tempa}}
       {\blx@postpunct}%
     \iftoggle{blx@block}%
       {\begingroup
          \let\blx@begunit\@empty
          \let\blx@endunit\@empty
          \let\blx@endnounit\@empty
          \newblockpunct
        \endgroup
        \global\togglefalse{blx@block}%
        \togglefalse{blx@tempa}}%
       {}}%
    {}%
  \blx@postpunct
  \blx@imc@resetpunctfont
  \iftoggle{blx@tempa}%
    {}%
    {\global\togglefalse{blx@insert}}%
  \csname a:blx@unit\endcsname
  \blx@leavevmode
  \begingroup
    \Configure{blx@unit}{}{}%
}
\def\blx@endunit{%
  \endgroup
  \csname b:blx@unit\endcsname%
  \Configure{blx@unit}{}{}%
  \global\toggletrue{blx@insert}%
  \global\toggletrue{blx@lastins}%
}
\NewConfigure{blx@unit}{2}

%
   \else
\fi

\ifdefined\XeTeXversion
  \def\abx@aux@defaultrefcontext#1#2#3{%        
  \csxdef{blx@assignedrefcontextbib@#1@\detokenize{#2}}{\detokenize{#3}}}
\fi
\renewrobustcmd*{\addnbspace}{%
  \unspace\blx@postpunct%
  % insert real non-breaking space character
  \nobreakspace\blx@imc@resetpunctfont}

   \NewConfigure{thebibliography}{4}
\append:def\blx@bibinit{\a:bibinit}%
\NewConfigure{bibinit}{1}%

   \let\blx@anchors\@empty
\let\bib@field@entrykey\@empty

\protected\def\blx@anchor{%
  \xifinlist{X\the\c@refsection -%@
    \bib@field@entrykey}{\blx@anchors}%
    {}%
    {\listxadd\blx@anchors{X\the\c@refsection -%@
      \bib@field@entrykey}%
     \hyper:natanchorstart{X\the\c@refsection -%@
      \bib@field@entrykey}%
     \hyper:natanchorend}}

\protected\def\blx@bibhyperref{%
   \@ifnextchar[%]
     {\blx@bibhyperref@i}%
     {\blx@bibhyperref@i[\bib@field@entrykey]}}%

\long\def\blx@bibhyperref@i[#1]#2{%
   \hyper:natlinkstart{X\the\c@refsection -%@
     #1}%
     #2\hyper:natlinkend}%

\protected\long\def\blx@bibhyperlink#1#2{%
   \hyper:natlinkstart{X\the\c@refsection -%:
     #1}%
     #2\hyper:natlinkend}%

\protected\long\def\blx@bibhypertarget#1#2{%
   \@bsphack
   \hyper:natanchorstart{X\the\c@refsection -%:
     #1}%
   \@esphack
     #2\hyper:natanchorend}%

\let\blx@ifhyperref\@firstoftwo

% Oleg Domanov [email protected] reports:
% tex4ht ends with an error when compiles biblatex files. I'm on
% Windows, texlive 2012. I put here a minimal example and files
% generated with the command latexmk test && mk4ht oolatex test
%
% https://www.dropbox.com/s/hn1zm40htqs13mf/t4htlink.zip
%
% There is a superfluous \relax in the file test.tmp, line 65 which
% seems to cause the error.
%
% Changes to cope with biblatex upgrade caused this problem. It is now
% fixed. --CVR 2012/10/26
%
\:CheckOption{ooffice}\if:Option
 \def\hyper:natanchorstart#1{\Link{}{#1}\EndLink}%
 \def\hyper:natlinkstart#1{\Link{#1}{}}%
\else
 \def\hyper:natanchorstart#1{%
      \expandafter\ifx\csname QXpage.\thepage\endcsname\relax%
        \Tag{)Qpage.\thepage}{\file:id}%
        \HCode{<a id="page.\thepage"></a>}%
        \expandafter\xdef\csname QXpage.\thepage\endcsname{0}%
       \fi
      \Link[\csname BibFileName\therefsection\endcsname]{}{#1}\EndLink}
 \def\hyper:natlinkstart#1{%
      \expandafter\ifx\csname QXpage.\thepage\endcsname\relax%
        \Tag{)Qpage.\thepage}{\file:id}%
        \HCode{<a id="page.\thepage"></a>}%
        \expandafter\xdef\csname QXpage.\thepage\endcsname{0}%
       \fi
      \Link[\csname BibFileName\therefsection\endcsname]{#1}{}}
\fi
\def\hyper:natanchorend{}
\def\hyper:natlinkend{\EndLink}
\def\writeCiteLink#1{\immediate\write\@mainaux{%
    \string\@namedef{#1.\thepage}{\FileName}}}
\let\blx@addpagesum\@gobbletwo
% \let\nolinkurl\relax

\ifx\blx:ver:no < 3
%
% biblatex 2.9a
%
% Newly added to process {keylist} environment (CVR)
%
\let\keylist\description
\let\endkeylist\enddescription
\def\keyitem#1{\item[#1]}%
%
%
\else
%
% biblatex 3.0
%
\let\keylist\Un:def
\let\endkeylist\Un:def
\newenvironment*{keylist}
  {\list{}{%
     \setlength{\labelwidth}{1.25in}%
     \setlength{\labelsep}{10pt}%
     \setlength{\leftmargin}{0pt}%
     \setlength{\itemsep}{0pt}%
     \raggedright%
     \renewcommand*{\makelabel}[1]{\hss\bfseries##1}}}
  {\endlist}
%
\def\keyitem#1{%
  \item[#1]
  \begingroup
    \keyitemhook%
    \blx@bibinit%
    \midsentence\ifbibstring{#1}{}{\latintext}\biblstring{#1}%
    \expandafter\lbx@initnamehook\lsmartoftext%
    \par\nobreak
    \midsentence\ifbibstring{#1}{}{\latintext}\bibsstring{#1}%
    \expandafter\lbx@initnamehook\ssmartoftext%
  \endgroup
  \par\nobreak}
\fi  % End of version boolean

\ConfigureList{keylist}%
   {\EndP\HCode{<dl \a:LRdir class="description">}%
      \PushMacro\end:itm
\global\let\end:itm=\empty}%
   {\PopMacro\end:itm \global\let\end:itm \end:itm
\EndP\HCode{</dd></dl>}\ShowPar}%
   {\end:itm \global\def\end:itm{\EndP\Tg</dd>}\HCode{<dt
        class="description">}\bgroup \bf}%
   {\egroup\EndP\HCode{</dt><dd\Hnewline class="description">}}

   \let\:temp\do
  \def\do#1{%
    \patchcmd#1%
      {\color@begingroup}%
      {\color@begingroup\toggletrue{blx@footnote}}%
      {\togglefalse{blx@tempa}\listbreak}%
      {}}%
  \docsvlist{%
    \@footnotetext,%          latex
    \H@@footnotetext,%        hyperref
    \scr@saved@footnotetext,% koma-script 3.x
    \l@dold@footnotetext,%    ledmac
    \l@doldold@footnotetext,% ledmac
    \@fntORI}%                frenchle
\let\do\:temp

   \pend:defI\blx@backref{%
  % prevent duplicate backlink on the same page
  \ifcsdef{bk##1\thepage}{}{%
    % insert link to the page
    \html:addr\Link-{}{x\last:haddr}\EndLink%
    % save link to the .xref file
    \Tag{)Q##1\thepage}{x\last:haddr}%
    % we need to save the link destination in .xref file
    % too, otherwise \Link command would issue warning
    \Tag{)Qx\last:haddr}{\FileNumber}%
  }%
  % declare this backlink destination as used, so we don't
  % declare another one with the same name
  \expandafter\gdef\csname bk##1\thepage\endcsname{}%
}

% version of \hyperlink that links back to saved link in citation
% on the given DVI page
\def\bbx:hyperlink#1#2{
  % first argument is destination used by Hyperref, second is page number
  % test if we saved link to the current bibitem and page
  \ifTag{)Q\abx@field@entrykey#2}{%
      \Link{\LikeRef{)Q\abx@field@entrykey#2}}{}#2\EndLink%
  }%
  {#2}% print just page number if there is no saved link
  }

% we need to redefine pageref format, which is used for printing of
% back link page numbers. custom \hyperlink command is used
\DeclareListFormat{pageref}{%
  % we redefine \hyperlink command to link page numbers in backreferences
  % back to the citations on the given pages
  \let\orig:hyperlink\hyperlink%
  \let\hyperlink\bbx:hyperlink%
  \ifnumless{\abx@pagerefstyle}{0}
    {\usebibmacro{list:plain}%
     \ifhyperref
       {\hyperlink{page.#1}{#1}}
       {#1}}
    {\ifnumequal{\value{listcount}}{1}
       {\usebibmacro{pageref:init}}
       {}%
     \usebibmacro{pageref:comp}{#1}%
     \ifnumequal{\value{listcount}}{\value{liststop}}
       {\usebibmacro{pageref:dump}}
       {}}
  \let\hyperlink\orig:hyperlink%
}


\Hinput{biblatex}
\endinput
Related Question