在 savebox 中缓存数学内容并考虑数学风格

Question

我在用在组中创建一个 \savebox，并使其在组外可用缓存一些数学内容。但是，我意识到可能存在需要为不同的数学风格缓存相同数学内容的情况。

scalerel我尝试使用正确使用数学选择并将其包含在样式中。但是，我无法将 的功能\SavedStyle应用于数学内容。下面的 MWE 产生：

\sqrt期望输出的分母较小：

代码：

\documentclass{article}
\usepackage{etoolbox}
\usepackage{xparse}
\usepackage{scalerel}

\NewDocumentCommand{\CachedMathContent}{s O{} m}{%
    % #1 = not used here
    % #2 = String to use to store cached name. 
    %      Declared as optional (for compatibility with another related macro), but 
    %      in this example it is really mandatory. 
    % ---------
    % Code to check that #2 was provided has been omitted here.
    \ThisStyle{% scalerel pacakge
        \begingroup
        \edef\CachedMathBoxName{MathBox #2 \string\SavedStyle}%
        \ifcsdef{\CachedMathBoxName}{%
            %% Cached content already exists
        }{%
            %% https://tex.stackexchange.com/questions/283373/create-a-savebox-in-a-group-and-have-it-available-outside-of-group
            \global\expandafter\newsavebox\csname\CachedMathBoxName\endcsname%
            \global\expandafter\setbox\csname\CachedMathBoxName\endcsname%
                    \hbox{$\SavedStyle#3$}%
        }%
        \expandafter\usebox\csname\CachedMathBoxName\endcsname%
        \endgroup
    }%
}%

\begin{document}

Should be cramped: $\frac{1}{\CachedMathContent[sqrt phi]{\sqrt{\phi}}}$

\medskip
Should NOT be cramped: $\CachedMathContent[sqrt phi]{\sqrt{\phi}}$ 

\end{document}

Answer 1

\documentclass{article}
\usepackage{etoolbox}
\usepackage{xparse}
\usepackage{scalerel}

\NewDocumentCommand{\CachedMathContent}{s O{} m}{%
    % #1 = not used here
    % #2 = String to use to store cached name. 
    %      Declared as optional (for compatibility with another related macro), but 
    %      in this example it is really mandatory. 
    % ---------
    % Code to check that #2 was provided has been omitted here.
    \ThisStyle{% scalerel pacakge
        \begingroup
\edef\x{\SavedStyle}%
\typeout{\meaning\x}%
        \edef\CachedMathBoxName{MathBox #2 \expandafter\string\x}%
        \ifcsdef{\CachedMathBoxName}{%
            %% Cached content already exists
        }{%
            %% http://tex.stackexchange.com/questions/283373/create-a-savebox-in-a-group-and-have-it-available-outside-of-group
\typeout{\meaning\CachedMathBoxName}%
            \global\expandafter\newsavebox\csname\CachedMathBoxName\endcsname%
            \global\expandafter\setbox\csname\CachedMathBoxName\endcsname%
                    \hbox{$\SavedStyle#3$}%
        }%
        \expandafter\usebox\csname\CachedMathBoxName\endcsname%
        \endgroup
    }%
}%

\begin{document}

Should be cramped: 
$\frac{1}{\CachedMathContent[sqrt phi]{\sqrt{\phi}}}$
$\frac{1}{\sqrt{\phi}}$

\medskip
Should NOT be cramped:
$\CachedMathContent[sqrt phi]{\sqrt{\phi}}$ 
$\sqrt{\phi}$ 

\end{document}

代码的目的是根据提供的参数和当前样式保存一个框，但是

    \edef\CachedMathBoxName{MathBox #2 \string\SavedStyle}%

使用并且它不使用#2文字字符串的定义（它根本不需要定义它）。\SavedStyle\SavedStyle

您需要将该宏完全扩展为类似内容\textstyle，然后\string应用于那因此\edef和\expandafter。