如何检查 biblatex 条目是否包含作者字段？

Question

我正在撰写一篇关于大量艺术作品的论文，并一直在尝试自动创建章节标题，但是当我尝试检查 Biblatex 作者条目是否真的存在时遇到了障碍。

我想做这样的事情：

\documentclass{article}

\usepackage[backend=biber]{biblatex}

\newcommand{\sectiontitle}[1]{\section{%
%check for author field in #1 and include "\citeauthor{#1} - " if it exists%
\citetitle{#1}}}

\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@ARTWORK{gizapyramid,
  title = {Pyramids at Gizeh},
  location = {Giza, Egypt},
  year = {ca.\@ 2500 BCE}
}
@ARTWORK{bar,
  title = {A Bar at the Folies-Berg\`{e}re},
  location = {London, England},
  year = {1882},
  author = {Manet, \'{E}douard}
}
\end{filecontents}
\addbibresource{\jobname.bib}

\begin{document}

\sectiontitle{bar}

\sectiontitle{gizapyramid}

\end{document}

为了达到与此相同的结果：

\documentclass{article}

\usepackage[backend=biber]{biblatex}

\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@ARTWORK{gizapyramid,
  title = {Pyramids at Gizeh},
  location = {Giza, Egypt},
  year = {ca.\@ 2500 BCE}
}
@ARTWORK{bar,
  title = {A Bar at the Folies-Berg\`{e}re},
  location = {London, England},
  year = {1882},
  author = {Manet, \'{E}douard}
}
\end{filecontents}
\addbibresource{\jobname.bib}

\begin{document}

\section{\citeauthor{bar} - \citetitle{bar}}

\section{\citetitle{gizapyramid}}

\end{document}

但是，我不确定如何进行检查才能完成此操作。我如何检查 Biblatex 作者条目是否确实存在并将其实现到我的代码中？

Answer 1

@lockstep 比我早了一两分钟，但这可能有点不同，所以我发布它，因为它可能在某些地方有用。

\documentclass{article}

\usepackage[backend=biber]{biblatex}

\makeatletter
\let\foo\blx@getdata@cite
\def\usefoo#1{\expandafter\expandafter\expandafter\@empty\csname abx@field@#1\endcsname}



\newcommand{\sectiontitle}[1]{%
\let\abx@name@author\relax\foo{#1}%
\section{%
\ifx\abx@name@author\relax
\else
\citeauthor{#1} --- %
\fi
\citetitle{#1}}}

\makeatother
\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@ARTWORK{gizapyramid,
  title = {Pyramids at Gizeh},
  location = {Giza, Egypt},
  year = {ca.\@ 2500 BCE}
}
@ARTWORK{bar,
  title = {A Bar at the Folies-Berg\`{e}re},
  location = {London, England},
  year = {1882},
  author = {\'{E}douard Manet}
}
\end{filecontents}
\addbibresource{\jobname.bib}

\begin{document}



\sectiontitle{bar}

\sectiontitle{gizapyramid}

\end{document}

Answer 2

包含测试的新引用命令\citeauthortitle（模仿）似乎可以解决问题。\citetitle\ifnameundef

\documentclass{article}

\usepackage[backend=biber]{biblatex}

\DeclareCiteCommand{\citeauthortitle}
  {\boolfalse{citetracker}%
   \boolfalse{pagetracker}%
   \usebibmacro{prenote}}
  {\ifciteindex
     {\indexfield{indextitle}}
     {}%
   \ifnameundef{author}{% NEW
   }{% NEW
     \printnames{labelname}~-- % NEW
   }% NEW
   \printfield[citetitle]{labeltitle}}
  {\multicitedelim}
  {\usebibmacro{postnote}}

\newcommand{\sectiontitle}[1]{\section{\citeauthortitle{#1}}}

\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@ARTWORK{gizapyramid,
  title = {Pyramids at Gizeh},
  location = {Giza, Egypt},
  year = {ca.\@ 2500 BCE}
}
@ARTWORK{bar,
  title = {A Bar at the Folies-Berg\`{e}re},
  location = {London, England},
  year = {1882},
  author = {Manet, \'{E}douard}
}
\end{filecontents}
\addbibresource{\jobname.bib}

\begin{document}

\sectiontitle{bar}

\sectiontitle{gizapyramid}

\end{document}

注意：我使用是\ifnameundef因为author字段在 中被视为“名称列表” biblatex。要测试“文字列表”，应该\iflistundef对其他字段使用\iffieldundef。