biblatex: numbering of "overlapping" bibliographies

Question

I have to create in a document two bibliographies (easy), which should be numbered (easy) which are filled by distinct \cite-commands (which can be done e.g. with categories). The problem is that it is possible that some bib-entries should be in both bibliographies and here the problems start as can be seen by this example:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[style=numeric,defernumbers,sortcites]{biblatex}
\DeclareBibliographyCategory{related}
\DeclareBibliographyCategory{main}

\DeclareCiteCommand{\cite}[\mkbibbrackets]
  {\usebibmacro{prenote}}
  {\addtocategory{main}{\thefield{entrykey}}%
   \usebibmacro{citeindex}%
   \usebibmacro{cite}}
  {\multicitedelim}
  {\usebibmacro{postnote}}

\DeclareCiteCommand{\citer}[\mkbibparens]
  {\usebibmacro{prenote}}
  {\addtocategory{related}{\thefield{entrykey}}%
   \usebibmacro{citeindex}%
   \usebibmacro{cite}}
  {\multicitedelim}
  {\usebibmacro{postnote}}

\addbibresource{biblatex-examples.bib}  

\begin{document}
\cite{shore,sarfraz,spiegelberg}

\citer{spiegelberg}

\cite{weinberg}

\citer{sigfridsson}


\printbibliography[category=main,title=Main List,resetnumbers]

\DeclareFieldFormat{labelnumberwidth}{\mkbibparens{#1}}
\printbibliography[category=related,resetnumbers,title=Related Documents]

\end{document}

The Spiegelberg entry should have number 3 in the first bibliography (and when cited by \cite, and 2 in the second and when cited by \citer. I have now been looking at refsection (would work, if one could "interrupt and resume" it), \DeclareSourceMap (to copy the entry) and other things but nothing looks really good. Has someone an idea how to do it?

Answer 1

I found two solutions to the question

With a recent version of biblatex (and biber 2.0)

There one can "clone" entries: (see also https://github.com/plk/biblatex/issues/297)

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[style=numeric,defernumbers,sortcites]{biblatex}
\DeclareBibliographyCategory{related}
\DeclareBibliographyCategory{main}
\DeclareCiteCommand{\cite}[\mkbibbrackets]
  {\usebibmacro{prenote}}
  {\addtocategory{main}{\thefield{entrykey}}%
   \usebibmacro{citeindex}%
   \usebibmacro{cite}}
  {\multicitedelim}
  {\usebibmacro{postnote}}
\DeclareCiteCommand{\citer}[\mkbibparens]
  {\usebibmacro{prenote}}
  {\addtocategory{related}{\thefield{entrykey}}%
   \usebibmacro{citeindex}%
   \usebibmacro{cite}}
  {\multicitedelim}
  {\usebibmacro{postnote}}
\addbibresource{biblatex-examples.bib}
\DeclareSourcemap{
  \maps[datatype=bibtex]{
    \map{
      \perdatasource{biblatex-examples.bib}
      \step[fieldsource=entrykey, match=\regexp{(.*)}, final]
      \step[entryclone={rel-$1}]
    }
  }
}
\begin{document}\nocite{*}
\cite{shore,sarfraz,spiegelberg}
\citer{rel-spiegelberg,rel-springer}
\printbibliography[category=main,title=Main List,resetnumbers]
\DeclareFieldFormat{labelnumberwidth}{\mkbibparens{#1}}
\printbibliography[category=related,resetnumbers,title=Related Documents]
\end{document}

Using "splitted refsections"

This puts the different cite commands in different refsections. The challenge here was to find a way to pause and restart a refsection. As refsection can't be nested one can't use this solution in documents with "real" refsections! A discussion about this solution is here https://github.com/plk/biblatex/issues/307. If I find some time I will perhaps convert it in a package.

updated 2018 to adapt to some internal changes in \blx@refsection@i.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[sortcites]{biblatex}
\usepackage{xparse,zref}
\addbibresource{biblatex-examples.bib}
\makeatletter
% Commands to label and reference the refsections
% by name. As a refsection can be behind
% \printbibliography a fallback label in the aux is used too
\newcommand\UFblx@labelrefsection[1]{%
 \csxdef{refsection@label@#1@num}{\the\c@refsection}%
 \zref@setcurrent{default}{\the\c@refsection}%
 \zref@labelbyprops{refsection@auxlabel@#1}{default}}
\newcommand\getrefsection[1]{%
 \ifcsname refsection@label@#1@num\endcsname
  \csname refsection@label@#1@num\endcsname
 \else
  \zref@extractdefault{refsection@auxlabel@#1}{default}{0}%
 \fi}
% a hook at the begin can be useful
\newcommand\splitrefinit[2]{%
 \csdef{UFblx@splitrefsection@#1@inithook}{#2}}
\newcommand\UFblx@refsectioncont@i{}
\newcommand\UF@refsectioncont@name{}
\def\UFblx@refsectioncont@i[#1]{%an adapted version of \blx@refsection@i
  \endgroup
  \ifcsdef{refsection@label@\csuse{UF@refsectioncont@name}@num}%
  {\blx@maxsection=\numexpr\csname refsection@label@\csuse{UF@refsectioncont@name}@num\endcsname\relax}%
  {\PackageWarning{test}{refsection \UF@refsectioncont@name\space unknown, using refsection 0}{}%
   \blx@maxsection=0
  }%
  \xifinlist{\the\c@refsection}\blx@allrefsections
    {}
    {\listxadd\blx@allrefsections{\the\c@refsection}}%
  \ifcsdef{blx@defaultrefcontexts@\the\c@refsection}
    {}
    {\global\cslet{blx@defaultrefcontexts@\the\c@refsection}@empty}%
  \ifcsdef{blx@maxsegment@\the\c@refsection}{}%
  {\expandafter\newcount\csname blx@maxsegment@\the\c@refsection\endcsname}%
  \ifcsdef{blx@sectionciteorder@\the\c@refsection}{}%
  {\expandafter\newcount\csname blx@sectionciteorder@\the\c@refsection\endcsname}%
  \global\c@refsection\blx@maxsection
  \blx@inf@refsec
  \blx@secinit
  \if@filesw
    \blx@auxwrite@mainaux{}{%
      \string\abx@aux@refsection{\the\c@refsection}{\the\c@page}}%
    \ifblank{#1}
      {}
      {\let\blx@bibfiles@empty
       % globals should be first as it might contain macros needed for others
       \forlistloop{\listadd\blx@bibfiles}\blx@bibfiles@global}%
       \blx@xsanitizeafter{\forcsvlist\blx@refsection@addfile}{#1}%
    \blx@refsection@ii
  \fi
  \endgroup}%
\ExplSyntaxOn
\tl_new:N\l_UFbbx_tmp_biblist_tl
\keys_define:nn {UFbbx}
 {
  name    .tl_set:N = {\UF@refsectioncont@name},
 }
\newenvironment{splitrefsection}[1][]%[2][]
{\keys_set_known:nnN {UFbbx} {#1} \l_UFbbx_tmp_biblist_tl
 %a hook
 \csname UFblx@splitrefsection@\csuse{UF@refsectioncont@name}@inithook\endcsname
 %test if new name
 \ifcsdef{refsection@label@\csuse{UF@refsectioncont@name}@num}
  {%continue known refsection
   \let\blx@refsection@i\UFblx@refsectioncont@i
   \expandafter\refsection\expandafter[\l_UFbbx_tmp_biblist_tl]
  }
  {%new labeled refsection:
   \expandafter\refsection\expandafter[\l_UFbbx_tmp_biblist_tl]
   \UFblx@labelrefsection{\UF@refsectioncont@name}
  }
 }
 {\endrefsection}
\ExplSyntaxOff
\NewDocumentCommand\splitrefcite {r<> o o m}
 {\begin{splitrefsection}[name=#1]%
  \let\mkbibbrackets\mkbibparens
  \IfNoValueTF{#3}
   {\IfNoValueTF{#2}
    {\cite{#4}}
    {\cite[#2]{#4}}}
    {\cite[#2][#3]{#4}}%
  \end{splitrefsection}}
\DeclareMultiCiteCommand{@splitrefcites}[@splitrefwrapper]{\cite}{\multicitedelim}
\newcommand@splitrefwrapper{}
\NewDocumentCommand\splitrefcites {r<>}
 {\renewcommand@splitrefwrapper[1]{\begin{splitrefsection}[name=#1]\mkbibparens{##1}\end{splitrefsection}}%
  @splitrefcites}
%for the example cites are in parens in splitref.
\splitrefinit{myrefsec}{\let\mkbibbrackets\mkbibparens}
\makeatother
\begin{document}
\cite{shore,sarfraz,spiegelberg}
\splitrefcite<related>{spiegelberg,springer}
\printbibliography[title=Main List]
\DeclareFieldFormat{labelnumberwidth}{\mkbibparens{#1}}
\printbibliography[section=\getrefsection{related},title=Related Documents]
\end{document}