使用 biblatex 和 babel 处理法语时如何删除小写字母？

Question

当我使用biblatex带authoryear样式时，所有内容都按我想要的方式显示。但是，当我添加时\usepackage[french]{babel}，引用和参考文献都以小写字母书写。有没有办法删除小写字母？

MWE 如下：

\documentclass{article}

\usepackage[utf8]{inputenc}
\usepackage[french]{babel}
\usepackage[backend = biber, style = authoryear]{biblatex}
\usepackage{filecontents}

\begin{filecontents}{biblio.bib}
@article{abel2018,
  title = {Estimates of {{Global Bilateral Migration Flows}} by {{Gender}} between 1960 and 2015},
  author = {Abel, Guy J.},
  date = {2018-09},
  journaltitle = {International Migration Review},
  shortjournal = {International Migration Review},
  volume = {52},
  pages = {809--852},
  doi = {10.1111/imre.12327},
  url = {http://journals.sagepub.com/doi/10.1111/imre.12327},
  urldate = {2019-12-14},
  langid = {english},
  number = {3}
}
\end{filecontents}

\addbibresource{biblio.bib}

\begin{document}
\cite{abel2018} and \parencite{abel2018}
\printbibliography
\end{document}

我拥有的：

我想要的是（“参考文献”重音）：

Answer 1

正如所讨论的https://tex.stackexchange.com/a/301571/134144和在 biblatex 中保留小写阻止biblatex法语模块以小写字母排版姓氏的正确解决方案是添加

\DefineBibliographyExtras{french}{\restorecommand\mkbibnamefamily}

biblatex在加载后的序言中。

---

正如评论中所说，原作者使用的是 R markdown，它是biblatex半自动加载的。将上面的行添加到序言中显然会产生以下形式的错误

! Undefined control sequence.
l.62 \DefineBibliographyExtras{french}{\restorecommand\mkbibnamefamily}

这表明该前导代码在biblatex加载之前就已执行。

在这种情况下

\usepackage{etoolbox}
\AtEndPreamble{\DefineBibliographyExtras{french}{\restorecommand\mkbibnamefamily}}

可能会有帮助。这两行将执行推迟\DefineBibliographyExtras到序言的末尾，此时 R markdown 应该已经加载，biblatex以便命令可用。

这在 MWE 中有效

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[french]{babel}

\usepackage{etoolbox}
\AtEndPreamble{\DefineBibliographyExtras{french}{\restorecommand\mkbibnamefamily}}

\usepackage[backend = biber, style = authoryear]{biblatex}

\addbibresource{biblatex-examples.bib}

\begin{document}
\cite{sigfridsson} and \parencite{sigfridsson}
\printbibliography
\end{document}