![`\futurelet` 如何获取 `\UTFviii@three@octets` 的替换宏?](https://linux22.com/image/473834/%60%5Cfuturelet%60%20%E5%A6%82%E4%BD%95%E8%8E%B7%E5%8F%96%20%60%5CUTFviii%40three%40octets%60%20%E7%9A%84%E6%9B%BF%E6%8D%A2%E5%AE%8F%EF%BC%9F.png)
我想用它\futurelet
来测试以下令牌。为此,我有一个如下所示的设置:
\makeatletter
\def\@ExpandSub{%
\typeout{Given Input: \meaning\@input}%
\typeout{Followup command: \meaning\@following}%
\ifx\@following\UTFviii@three@octets% <--- doesn't work!
\typeout{>>> That's unicode!}%
\else%
\typeout{>>> That's NOT unicode...}%
\fi%
}
\protected\def\sub#1{%
\let\@input#1%
\futurelet\@following\@ExpandSub%
}
\makeatother
- 我如何测试下一个标记是否为 Unicode 字符
\ifx\@following\UTFviii@three@octets
不起作用,我认为是因为\@following
保存了一个受保护的宏,\UTFviii@three@octets
而不是\UTFviii@three@octets
它本身。日志显示:Followup command: \protected macro:->\UTFviii@three@octets �
,但我想要替换宏,因为它是在里面指定的\newunicodechar
。 - 如果是这种情况,我如何才能获得定义的替代宏
\newunicodechar
?
这是尝试实现自动将 unicode 双下标 aᵢⱼ = a_{i}_{j} 合并为 a_{ij}。
完整演示\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{etoolbox}
\usepackage{newunicodechar}
\makeatletter
\newtoggle{insub}
\def\@ExpandSub{%
\typeout{Given Input: \meaning\@input}%
\typeout{Followup command: \meaning\@following}%
% if \@following is \UTFviii@three@octets, get the replacement text
\ifx\@following\UTFviii@three@octets% <--- doesn't work!
\typeout{>>> That's unicode!}%
\else%
\typeout{>>> That's NOT unicode...}%
\let\@actual\@following
\fi%
\iftoggle{insub}{
\@input%
}{
\toggletrue{insub}%
\sb\bgroup\@input%
}%
\ifx\@actual\sub%
\typeout{keep going!}%
\else%
\typeout{Stop!}%
\egroup\togglefalse{insub}%
\fi%
}
% \DeclareRobustCommand*{\sub}[1]{\futurelet\@following\@ExpandSub{#1}}
\protected\def\sub#1{%
\let\@input#1%
\futurelet\@following\@ExpandSub%
}
\makeatother
\AtBeginDocument{
\newunicodechar{ᵢ}{\sub{i}}
\newunicodechar{ⱼ}{\sub{j}}
\newunicodechar{ₖ}{\sub{k}}
\newunicodechar{ₗ}{\sub{l}}
\newunicodechar{ₘ}{\sub{m}}
\newunicodechar{ₙ}{\sub{n}}
}
\begin{document}
\begin{tabular}{l}
$a_{ijklmn}$ \\
%$a\chain{i}\chain{j}\chain{k}\chain{l}\chain{m}\chain{n}$ \\
$a\sub{i}\sub{j}\sub{k}\sub{l}\sub{m}\sub{n}$ \\
% $a\sub[i]\sub[j]\sub[k]\sub[l]\sub[m]\sub[n]$ \\
$aᵢⱼₖₗₘₙ$
\end{tabular}
\end{document}
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