\ProvidesPackage{biblatex-ext-tabular}
  [2019/08/25 v0.8 tabular bibliographies for biblatex (MW)]

% Code based on Audrey's
% (https://tex.stackexchange.com/users/4483/audrey)
% answer https://tex.stackexchange.com/a/71454/35864 on TeX.SX
% relicensed under CC0, see
% https://tex.meta.stackexchange.com/a/1755/35864
% ultimately based on LPPL code from biblatex.sty
% Additional modifications by me in
% https://tex.stackexchange.com/a/440356/35864

\protected\def\extblxtab@error#1#2{%
  \PackageError{biblatex-ext-tabular}{#1}{#2.}}

\protected\def\extblxtab@warning@noline{%
  \PackageWarningNoLine{biblatex-ext-tabular}}

\let\extblxtab@warning\extblxtab@warning@noline
\AtEndOfPackage{%
  \protected\def\extblxtab@warning{%
    \PackageWarning{biblatex-ext-tabular}}}

% user-level command for printing tabular bibliography

\newrobustcmd*{\printbibtabular}{%
  \begingroup % closed in \extblxtab@bibtabular
  \delimcontext{bib}%
  \edef\on@line{\on@line}%
  \@ifnextchar[%]
    {\extblxtab@printbibtabular}
    {\extblxtab@printbibtabular[]}}

\def\extblxtab@key@env#1{%
  \ifcsundef{extblxtab@env@#1}
     {\extblxtab@error
        {Environment '#1' not found}
        {The environment '#1' could not be found.\MessageBreak
         Use \string\defbibtabular\space to define it}}
     {\def\blx@theenv{#1}}}

\def\extblxtab@printbibtabular[#1]{%
  \toggletrue{blx@tempa}%
  \toggletrue{blx@tempb}%
  \def\blx@theheading{bibliography}%
  \def\blx@theenv{bibtabular}%
  \let\blx@theprenote\@empty
  \let\blx@thepostnote\@empty
  \let\blx@thetitle\@empty
  \let\blx@key@env\extblxtab@key@env % redirect the 'env' option
                                     % to tabular envs
  % defaults
  \let\blx@tempa\@empty% before there is a .bbl, this must not be undef
  \edef\blx@tempe{\the\c@refsection}% default refsection is current
  \blx@safe@actives
  \togglefalse{blx@resetnumsexplicit}%
  % First pass options keys - section and resetnumbers
  \setkeys{blx@bib1}{#1}%
  % Is there a user-specified option for resetnumbers
  % If so, this overrides the default
  % "labelprefix implies resetnumbers" behaviour
  \iftoggle{blx@resetnumsexplicit}
    {}
    {\ifdefempty\blx@refcontext@labelprefix
      {}
      {\setkeys{blx@bib2}{resetnumbers}}}%
  \blx@rest@actives
  \ifcsvoid{blx@dlist@entry@\blx@tempe @\blx@refcontext@context}
    {}
    {\letcs\blx@tempa{blx@dlist@entry@\blx@tempe
                      @\blx@refcontext@context}}%
  \blx@safe@actives
  % Must reset omitnumbers as it's a global macro and if we don't, any
  % \printbibliography following one with this set will inherit any
  % previous "true" value
  \togglefalse{blx@omitnumbers}%
  \setkeys{blx@bib2}{#1}% ... now we have correct \blx@tempa,
  % set rest of options
  \blx@rest@actives
  % Add datalist to list of seen datalists to prevent duplicates
  \xifinlist{\blx@refcontext@context @\blx@tempe @entry}\blx@dlistnames
    {}
    {\listxadd\blx@dlistnames{\blx@refcontext@context @\blx@tempe
                              @entry}%
     \csxappto{blx@dlists}{%
       \blx@xml@dlist{\blx@refcontext@context}{entry}{\blx@tempe}{%
         \blx@xml@dlist@refcontext
           {\blx@refcontext@sortingtemplatename}
           {\blx@refcontext@sortingnamekeytemplatename}
           {\blx@refcontext@labelprefix}
           {\blx@refcontext@uniquenametemplatename}
           {\blx@refcontext@labelalphanametemplatename}}{}}}%
  \ifdefvoid\blx@tempa
    {\blx@warn@bibempty\endgroup}
    {\extblxtab@bibtabular\blx@tempa}}

% underlying macros
\def\extblxtab@bibtabular#1{%
  \blx@langstrings
  \blx@bibheading\blx@theheading\blx@thetitle
  \blx@bibnote\blx@theprenote
  \begingroup
  \blx@bibinit
  \let\@noitemerr\@empty
  \let\blx@noitem\blx@warn@bibempty
  \ifnum\bibinitsep=\z@
    \let\blx@initsep\relax
  \fi
  \ifnum\bibnamesep=\z@
    \let\blx@namesep\relax
  \fi
  \csuse{blx@hook@bibinit}%
  \csuse{blx@hook@bibinit@next}%
  % copy filtered list of entries to internal list macro
  \let\blx@tempb\@empty
  \def\blx@do##1{%
    \blx@ifdata{##1}{%
      \begingroup
      \blx@getdata{##1}%
      \blx@bibcheck
      \iftoggle{blx@skipentry}{}{%
        \global\let\blx@noitem\@empty
        \listgadd\blx@tempb{##1}}%
      \endgroup}{}}%
  \let\blx@done\relax
  \blx@listloop{#1}%
  \begingroup
  % sane names for wrapper macros
  \def\plain     {\extblxtab@tab@item@plain
                    {\extblxtab@tabrow@entrykey}}%
  \def\plainlang {\extblxtab@tab@item@plainlang
                    {\extblxtab@tabrow@entrykey}}%
  \def\anchor    {\extblxtab@tab@item@anchor
                    {\extblxtab@tabrow@entrykey}}%
  \def\anchorlang{\extblxtab@tab@item@anchorlang
                    {\extblxtab@tabrow@entrykey}}%
  \def\driver    {\extblxtab@tab@item@driver
                    {\extblxtab@tabrow@entrykey}}%
  % tabular output for each item in list
  % note that each cell is in its own group, hence we need \gdef to
  % break out of the first cell as soon as the row format has a & in it
  % since the assignment will be counted as being in the first cell
  \def\do##1{%
    \gdef\extblxtab@tabrow@entrykey{##1}%
    \csuse{extblxtab@tabrow@format@\blx@theenv}}%
  \csuse{extblxtab@env@\blx@theenv}%
  \dolistloop{\blx@tempb}%
  \csuse{extblxtab@endenv@\blx@theenv}%
  \endgroup
  \blx@bibnote\blx@thepostnote
  \endgroup
  \endgroup % this closes the group opened by \printbibtabular
}

\def\extblxtab@tab@item@aux@lang#1{%
  \blx@initunit
  \blx@beglangbib
  \bibsentence
  #1%
  \blx@postpunct
  \blx@endlangbib
}

\def\extblxtab@tab@item@plain#1#2{%
  \begingroup
  \blx@getdata{#1}%
  \blx@setoptions@type\abx@field@entrytype
  \blx@setoptions@entry
  \blx@thelabelnumber
  \csuse{blx@hook@bibitem}%
  \blx@execute
  #2%
  \endgroup
}

\def\extblxtab@tab@item@plainlang#1#2{%
  \extblxtab@tab@item@plain{#1}{%
    \extblxtab@tab@item@aux@lang{#2}}}

\def\extblxtab@tab@item@anchor#1#2{%
  \extblxtab@tab@item@plain{#1}{%
    \addtocounter{instcount}\@ne
    \blx@anchor
    \blx@pagetracker
    #2}}

\def\extblxtab@tab@item@anchorlang#1#2{%
  \extblxtab@tab@item@anchor{#1}{%
    \extblxtab@tab@item@aux@lang{#2}}}

\def\extblxtab@tab@item@driver#1#2{%
  \begingroup
  \blx@getdata{#1}%
  \blx@setdefaultrefcontext{#1}%
  \blx@setoptions@type\abx@field@entrytype
  \blx@setoptions@entry
  \blx@thelabelnumber
  \csuse{blx@hook@bibitem}%
  \blx@execute
  #2%
  \blx@initunit
  \blx@beglangbib
  \bibsentence
  \blx@driver\abx@field@entrytype
  \blx@postpunct
  \blx@endlangbib
  \endgroup
}

% user-level command for defining tabular bibliography format
\newrobustcmd*{\defbibtabular}[4]{%
  \long\csdef{extblxtab@env@#1}{#2}%
  \long\csdef{extblxtab@endenv@#1}{#3}%
  \long\csdef{extblxtab@tabrow@format@#1}{#4}}

% error message in case user does not initialise bibtabular
\defbibtabular{bibtabular}
  {\extblxtab@error{%
     tabular bibliography environment\MessageBreak
     'bibtabular' undefined}
     {Please supply a suitable definition with \string\defbibtabular.%
      \MessageBreak
      See the documentation for more details}}
  {\textbf{Error!
           The tabular bibliography environment `bibtabular' is
           undefined.
           No tabular bibliography was produced.
           Please supply a suitable definition with
           \mbox{\string\defbibtabular}.
           See the manual for more information.}}
  {}

\newrobustcmd*{\defbibtabulartwocolumn}[5]{%
  \long\csdef{extblxtab@env@#1}{#2}%
  \long\csdef{extblxtab@endenv@#1}{#3}%
  \long\csdef{extblxtab@tabrow@format@#1}{%
    \anchorlang{#4} & \driver{#5}\\
  }%
}

% Two useful bibmacros for tabular bibliographies

% print the labelname/sortname with editor or translator string if
% appropriate
\newbibmacro*{tabular:sortname}{%
  \ifnameundef{labelname}
    {\usebibmacro{labeltitle}}
    {\printnames[sortname]{labelname}%
     \iffieldequalstr{labelnamesource}{editor}
       {\setunit{\printdelim{editortypedelim}}%
        \usebibmacro{editor+othersstrg}}
       {\iffieldequalstr{labelnamesource}{translator}
          {\setunit{\printdelim{translatortypedelim}}%
           \usebibmacro{translator+othersstrg}}
          {}}}}

% bibitem hook to suppress redundant sortname list
% useful for \driver since it usually lives in its own group
\newbibmacro*{tabular:omitsortname}{%
  \ifnameundef{labelname}
    {}
    {\clearname{\thefield{labelnamesource}}}}

\endinput
%
% This file is part of the biblatex-ext bundle.
% biblatex-ext is released under the LaTeX Project Public License v1.3c
% or later.
%
% A complete list of files included in that package can be found in
% README.md or - failing that - in ext-standard.bbx.
%
% Official releases of this package are on CTAN
%   https://www.ctan.org/pkg/biblatex-ext
% development takes place on GitHub
%   https://github.com/moewew/biblatex-ext
%