`defbibenvironment` 中的嵌套列表

Question 1

好吧，自从我问了之后，我已经找到了一个令人满意的（即使不是理想的）解决方案。我会把它作为答案发布出来，因为它可能会有用。但其他答案仍然非常受欢迎。

更新：我可以改进这个解决方案（见下面的更新），以获得非常好的结果，从输出和使用的角度来看，没有什么可挑剔的。但是，这远非易事。我会接受这个答案，因为它确实解决了 OP，但如果有人想尝试更简单的东西，我会很乐意改变这一点。

我设法安排了一个解决方案，将感兴趣的条目组交织在一起，printbiblist为每个条目发布一个条目，并沿着手动提供的列表中提供的一组母条目循环。还引入了一些检查，以确保没有遗漏任何内容。

\RequirePackage{filecontents}

\begin{filecontents}{\jobname.bib}
@customa{natarch,
    title = {National Archives. But with a title long enough to span two lines. Yet a little longer},
    sortshorthand = {NatArch},
}

@customb{natarch:presabc,
    title = {President ABC Papers. A subtitle to let it reach a second line},
    shorthand = {NatArch -- ABC},
    sortshorthand = {NatArch -- ABC},
    xref = {natarch},
}

@customb{natarch:mintru,
    title = {Ministry of Truth Papers. Fully and continuously updated},
    shorthand = {NatArch -- MT},
    sortshorthand = {NatArch -- MT},
    xref = {natarch},
}

@customa{libcong,
    title = {Library of Congress},
    sortshorthand = {LibCon},
}

@customb{libcong:digcoll,
    title = {Digital Collections of the Library of Congress. But with a title long enough to span two lines},
    shorthand = {LibCon -- DC},
    sortshorthand = {LibCon -- DC},
    xref = {libcong},
}

\end{filecontents}

\documentclass{article}

\usepackage[style=authortitle,minxrefs=1]{biblatex}

\usepackage{calc}

\addbibresource{\jobname.bib}

% Providing bibdrivers

\DeclareBibliographyDriver{customa}{%
    \usebibmacro{bibindex}%
    \usebibmacro{begentry}%
    \printfield{title}%
    \newunit\newblock
    \printlist{location}%
    \usebibmacro{finentry}}
    
\DeclareBibliographyDriver{customb}{%
    \usebibmacro{bibindex}%
    \usebibmacro{begentry}%
    \printfield{title}%
    \usebibmacro{finentry}}

%Providing structure for biblist “primary”

\DeclareBiblistFilter{primary}{
    \filteror{
        \filter[type=type,filter=customa]
        \filter[type=type,filter=customb]
    }
}
    
\DeclareBibliographyDriver{primary}{%
    \usedriver{}{\thefield{entrytype}}%
    \usebibmacro{finentry}}

\DeclareBiblistFilter{primary}{
    \filteror{
        \filter[type=type,filter=customa]
        \filter[type=type,filter=customb]
    }
}

\DeclareSortingTemplate{primary}{
  \sort{
    \field{sortshorthand}
  }
  \sort{
    \field{shorthand}
  }
}

% Defining the two bibenvironments to be used in “primary” biblists

\defbibenvironment{primaryarchive}
  {\list
     {}
     {\setlength{\leftmargin}{\bibhang}%
      \setlength{\itemindent}{-\leftmargin}%
      \setlength{\itemsep}{\bibitemsep}%
      \setlength{\parsep}{\bibparsep}%
      \setlength{\topsep}{0pt}%
      \setlength{\partopsep}{2pt plus1pt minus1pt}}}
  {\endlist}
  {\item}

\defbibenvironment{primary}
  {\list
     {\printfield[shorthandwidth]{shorthand}}
     {\setlength{\labelwidth}{\shorthandwidth}%
      \setlength{\leftmargin}{\labelwidth}%
      \setlength{\labelsep}{\biblabelsep}%
      \addtolength{\leftmargin}{.5\bibhang}%
      \addtolength{\leftmargin}{\labelsep}%
      \setlength{\itemsep}{\bibitemsep}%
      \setlength{\parsep}{\bibparsep}%
      \setlength{\topsep}{0pt}%
      \setlength{\partopsep}{0pt}%
      \renewcommand*{\makelabel}[1]{##1\hss}}}
  {\endlist}
  {\item}

% Providing structure for a check if entries have not been forgotten

\DeclareBibliographyCategory{primarysources}
\DeclareBibliographyCategory{alreadyinprimarylists}

\AtDataInput[customa]{\addtocategory{primarysources}{\thefield{entrykey}}}
\AtDataInput[customb]{\addtocategory{primarysources}{\thefield{entrykey}}}

\AtEveryBiblistitem{primary}{\addtocategory{alreadyinprimarylists}{\thefield{entrykey}}}

% The individual biblists are screened by keyword, this adds a keyword for both mother and child entrys equal to the entrykey of the mother entry

\DeclareSourcemap{
    \maps[datatype=bibtex]{
        \map[overwrite]{
            \pertype{customb}
            \step[fieldsource=xref]
            \step[fieldset=keywords,fieldvalue={,},append]
            \step[fieldset=keywords,origfieldval,append]
            \step[fieldsource=keywords,match=\regexp{^,},replace={}]
        }
        \map[overwrite]{
            \pertype{customa}
            \step[fieldsource=entrykey]
            \step[fieldset=keywords,fieldvalue={,},append]
            \step[fieldset=keywords,origfieldval,append]
            \step[fieldsource=keywords,match=\regexp{^,},replace={}]
        }
    }
}

% Provides commands to print mother and child entries for each group, and a command to iterate along them

\newcommand{\printarchive}[1]{%
    \printbiblist[env=primaryarchive,heading=none,type=customa,keyword=#1]{primary}
    \printbiblist[heading=none,type=customb,keyword=#1]{primary}%
}
\newcommand{\printarchives}[1]{%
    \forcsvlist{\printarchive}{#1}%
}

% Just formatting
\DeclareFieldFormat[customa,customb]{title}{#1}

\begin{document}

\nocite{libcong:digcoll,natarch:mintru,natarch:presabc}

% Prints primary sources
\printbibheading[title={Primary sources}]
\printarchives{libcong,natarch}

% Checks if nothing has been forgotten
\defbibnote{warningmissingprimsources}{\mkbibbold{These entries should have been printed in the primary sources biblists above. If their were not, they are listed here which means that something is amiss and these entries should be handled until this warning is gone.}}
\printbibliography[title={Missing primary sources},prenote=warningmissingprimsources,category=primarysources,notcategory=alreadyinprimarylists]

% For comparison
\printshorthands
\printbibliography

\end{document}

结果正如我们所期望的：

还缺少什么：

母条目列表仍是手动提供的。这意味着我必须引入一些复杂的检查来处理最终的“杂散条目”。更重要的是，排序也是按照手动提供的列表的顺序进行的。可能有一种方法可以生成包含所有customa条目的列表，根据定义的排序方案对其进行排序并将其提供给printarchives。但我想不出。因此，正如最初所说的那样，其他完成此方法或完全采用另一种方法的答案仍然非常受欢迎。

更新：我找到了一种生成条目排序列表的方法customa。它涉及创建一个辅助printbiblist，其中包含 bibfilter、排序方案等，对该 biblist 进行错误运行并使用它来填充 etoolbox 列表，然后将其提供给printarchives。对于那些最终感兴趣的人：

\RequirePackage{filecontents}

\begin{filecontents}{\jobname.bib}
@customa{natarch,
    title = {National Archives. But with a title long enough to span two lines. Yet a little longer},
    sortshorthand = {NatArch},
}

@customb{natarch:presabc,
    title = {President ABC Papers. A subtitle to let it reach a second line},
    shorthand = {NatArch -- ABC},
    sortshorthand = {NatArch -- ABC},
    xref = {natarch},
}

@customb{natarch:mintru,
    title = {Ministry of Truth Papers. Fully and continuously updated},
    shorthand = {NatArch -- MT},
    sortshorthand = {NatArch -- MT},
    xref = {natarch},
}

@customa{libcong,
    title = {Library of Congress},
    sortshorthand = {LibCon},
}

@customb{libcong:digcoll,
    title = {Digital Collections of the Library of Congress. But with a title long enough to span two lines},
    shorthand = {LibCon -- DC},
    sortshorthand = {LibCon -- DC},
    xref = {libcong},
}

\end{filecontents}

\documentclass{article}

\usepackage[style=authortitle,minxrefs=1]{biblatex}

\usepackage{calc}

\addbibresource{\jobname.bib}

% Providing bibdrivers

\DeclareBibliographyDriver{customa}{%
    \usebibmacro{bibindex}%
    \usebibmacro{begentry}%
    \printfield{title}%
    \newunit\newblock
    \printlist{location}%
    \usebibmacro{finentry}}
    
\DeclareBibliographyDriver{customb}{%
    \usebibmacro{bibindex}%
    \usebibmacro{begentry}%
    \printfield{title}%
    \usebibmacro{finentry}}

%Providing structure for biblist “primary”

\DeclareBiblistFilter{primary}{
    \filteror{
        \filter[type=type,filter=customa]
        \filter[type=type,filter=customb]
    }
}
    
\DeclareBibliographyDriver{primary}{%
    \usedriver{}{\thefield{entrytype}}%
    \usebibmacro{finentry}}

\DeclareBiblistFilter{primary}{
    \filteror{
        \filter[type=type,filter=customa]
        \filter[type=type,filter=customb]
    }
}

\DeclareSortingTemplate{primary}{
  \sort{
    \field{sortshorthand}
  }
  \sort{
    \field{shorthand}
  }
}

% Defining the two bibenvironments to be used in “primary” biblists

\defbibenvironment{primaryarchive}
  {\list
     {}
     {\setlength{\leftmargin}{\bibhang}%
      \setlength{\itemindent}{-\leftmargin}%
      \setlength{\itemsep}{\bibitemsep}%
      \setlength{\parsep}{\bibparsep}%
      \setlength{\topsep}{0pt}%
      \setlength{\partopsep}{2pt plus1pt minus1pt}}}
  {\endlist}
  {\item}

\defbibenvironment{primary}
  {\list
     {\printfield[shorthandwidth]{shorthand}}
     {\setlength{\labelwidth}{\shorthandwidth}%
      \setlength{\leftmargin}{\labelwidth}%
      \setlength{\labelsep}{\biblabelsep}%
      \addtolength{\leftmargin}{.5\bibhang}%
      \addtolength{\leftmargin}{\labelsep}%
      \setlength{\itemsep}{\bibitemsep}%
      \setlength{\parsep}{\bibparsep}%
      \setlength{\topsep}{0pt}%
      \setlength{\partopsep}{0pt}%
      \renewcommand*{\makelabel}[1]{##1\hss}}}
  {\endlist}
  {\item}


% Provides structure for "auxiliary" biblist
% Used to generate a sorted list of customa (mother) entries

\DeclareBiblistFilter{auxiliary}{
        \filter[type=type,filter=customa]
}

\DeclareSortingTemplate{auxiliary}{
    \sort{
        \field{title}
    }
}

\DeclareBibliographyDriver{auxiliary}{}

\defbibenvironment{auxiliary}
  {\list
     {}
     {\setlength{\itemsep}{0pt}%
      \setlength{\parsep}{0pt}%
      \setlength{\topsep}{0pt}%
      \setlength{\partopsep}{0pt}}}
  {\endlist}
  {}

\AtEveryBiblistitem{auxiliary}{\listxadd{\sortedcustomalist}{\thefield{entrykey}}}

% The individual biblists are screened by keyword, this adds a keyword for both mother and child entrys equal to the entrykey of the mother entry

\DeclareSourcemap{
    \maps[datatype=bibtex]{
        \map[overwrite]{
            \pertype{customb}
            \step[fieldsource=xref]
            \step[fieldset=keywords,fieldvalue={,},append]
            \step[fieldset=keywords,origfieldval,append]
            \step[fieldsource=keywords,match=\regexp{^,},replace={}]
        }
        \map[overwrite]{
            \pertype{customa}
            \step[fieldsource=entrykey]
            \step[fieldset=keywords,fieldvalue={,},append]
            \step[fieldset=keywords,origfieldval,append]
            \step[fieldsource=keywords,match=\regexp{^,},replace={}]
        }
    }
}

% Provides an invisible box to perform false run of "auxiliary"
% from https://tex.stackexchange.com/a/22358/105447
\def\falserunbiblist#1{\edef\theprevdepth{\the\prevdepth}\nointerlineskip
  \vbox to0pt{#1\vss}\prevdepth=\theprevdepth}

% Provides commands to print mother and child entries for each group, and a command to iterate along them

\newcommand{\printarchive}[1]{%
    \printbiblist[env=primaryarchive,heading=none,type=customa,keyword=#1]{primary}
    \printbiblist[heading=none,type=customb,keyword=#1]{primary}%
}

\newcommand*{\sortedcustomalist}{}

\newcommand{\printarchives}{%
    \falserunbiblist{\printbiblist[heading=none]{auxiliary}} % This generates the list for the loop below
    \forlistloop{\printarchive}{\sortedcustomalist}
}

% Just formatting
\DeclareFieldFormat[customa,customb]{title}{#1}

\begin{document}

\nocite{libcong:digcoll,natarch:mintru,natarch:presabc}

% Prints primary sources
\printbibheading[title={Primary sources}]
\printarchives

% For comparison
\printshorthands
\printbibliography

\end{document}

Answer