引用时将命名定理名称的大多数字母改为小写

Question

如果您确定受到\NoCaseChange保护，则可以使用 Heiko Oberdiek 的 refcount 包中的宏来定义您自己的漂亮宏，确保在传递给之前通过扩展提取形成所需名称的短语\MakeTextLowercase：

\documentclass{article}
\usepackage[left=0.75in,right=0.75in]{geometry}

\usepackage{textcase}

\usepackage{amsthm}
\usepackage{thmtools}
\swapnumbers

\makeatletter
\declaretheoremstyle[
  headfont= \bfseries,
  headpunct={\bfseries.},
  postheadspace=0.5em,
  notefont=\bfseries,
  headformat=\NAME\NUMBER\let\thmt@space\@empty\NOTE,
  bodyfont=\mdseries\itshape,
  spaceabove=12pt,spacebelow=12pt,
]{thmstyle}    
\declaretheoremstyle[
  headfont=\bfseries,
  notefont=\bfseries, notebraces={}{},
  headformat=\NUMBER\let\thmt@space\@empty\NOTE,
  bodyfont=\mdseries\itshape,
  spaceabove=12pt,spacebelow=12pt,
]{namedthmstyle}
\makeatother

\theoremstyle{thmstyle}
\declaretheorem[name=Theorem,numberwithin=section]{theorem}
\declaretheorem[
  style=namedthmstyle,name=Theorem,title = {},numberlike=theorem
]{namedtheorem}

\usepackage{refcount}[2010/12/01 v3.2] %!!!!!
\usepackage[pdftex]{hyperref}
\hypersetup{colorlinks,linkcolor=red}
\usepackage[nameinlink,noabbrev,capitalize]{cleveref}

\usepackage{crossreftools}

\makeatletter
\@ifdefinable\MyNiceLowercaseNameref{%
  \DeclareRobustCommand\MyNiceLowercaseNameref{%
    \@ifstar{\MyNiceLowercaseNamerefAtStar}{\MyNiceLowercaseNamerefAtNoStar}%
  }%
}%
\newcommand\MyNiceLowercaseNamerefAtStar[1]{%
  \MyNiceGenericLowercaseNameref{\@firstofone}{#1}%
}%
\newcommand\MyNiceLowercaseNamerefAtNoStar[1]{%
  \MyNiceGenericLowercaseNameref{\hyperref[{#1}]}{#1}%
}%
\newcommand\MyNiceGenericLowercaseNameref[2]{%
  \refused{#2}%
  #1%
  {%
    \expandafter\expandafter\expandafter\MakeTextLowercase
    \expandafter\expandafter\expandafter{%
      \getrefbykeydefault{#2}{name}{%
        \nfss@text{\reset@font\bfseries ??}%
      }%
    }%
  }%
}%
\makeatother

\begin{document}

\section{The theorems}

\begin{theorem}[equalities of \MakeUppercase{E}uclid]
  \label{thm:prelim}
  $a = b$ and $b = c$

\end{theorem}

%!!!!!!!!!!!!!!!!!! \protect\NoCaseChange
\begin{namedtheorem}[name=Fundamental Theorem of \protect\NoCaseChange{Euler}]
  \label{thm:euler}
  $a = c$.
\end{namedtheorem}

\bigskip   
\emph{Original text of name:} Fundamental Theorem of Euler

\bigskip    
\emph{Desired modification:} fundamental theorem of Euler

\bigskip    
\emph{Attempts:}

\begin{itemize}

\item

\MakeTextLowercase{Fundamental Theorem of \NoCaseChange{Euler}} ---\verb!\MakeTextLowercase{Fundamental Theorem of \NoCaseChange{Euler}}!\\
works OK directly.

\item

\MakeTextLowercase{\nameref*{thm:euler}} --- \verb!\MakeTextLowercase{\nameref*{thm:euler}}! \\
of no use.

\item

\crtnameref*{thm:euler} --- \verb!\crtnameref*{thm:euler}!\\
try starting here now.

\item

%\MakeTextLowercase{\crtnameref*{thm:euler}} ---
\verb!\MakeTextLowercase{\crtnameref*{thm:euler}}! causes error:

\begin{verbatim}
./try.tex:84: Missing \endcsname inserted.
<to be read again> 
                   \relax 
l.84 \MakeTextLowercase{\crtnameref*{thm:euler}}

? x
\end{verbatim}


\item

\MyNiceLowercaseNameref{thm:euler} --- \verb!\MyNiceLowercaseNameref{thm:euler}!\\
seems to work out

\item

\MyNiceLowercaseNameref*{thm:euler} --- \verb!\MyNiceLowercaseNameref*{thm:euler}! \\
seems to work out

\end{itemize}

\end{document}

顺便一提：

命令\label、\ref和\pageref（以及其他一些命令）已得到 textcase 包的特殊处理，因为这些命令会触发应用于\NoCaseChange自身及其在\MakeTextLowercase/内的参数MakeTextUppercase。
但是，例如，命令\nameref（以及许多其他未出现在 LaTeX 2ε 内核中但在某些包中定义的命令）没有得到这种特殊处理。

因此，我强烈建议将其包装到\NoCaseChange任何应进入参数的引用命令中\MakeTextLowercase：

如果不这样做，非内核引用命令的引用标签名称也将变为小写。

假设您有引用标签foo和FOO：

\MakeTextLowercase{\nameref{FOO}}将创建对的引用foo，而不是的引用FOO。
\MakeTextLowercase{\NoCaseChange{\nameref{FOO}}}将创建对的引用FOO。

或者，看看你自己的例子：

\MakeTextLowercase{\nameref*{thm:euler}}很不错，不会触发有关未定义引用的警告。（不幸的是，它无法将所需的短语转换为小写形式。）

但是关于：

\MakeTextLowercase{\nameref*{THM:EULER}}？这难道不会触发有关未定义引用的警告吗？不会。因为THM:EULER转换为小写thm:euler，并且该标签已定义。

Answer 1