我正在使用 KOMAscript 的类编写文档scrreprt，并且正在编写自定义宏（\xref）来格式化用于交叉引用的文本。
该宏将标签名称作为参数：\xref{mylabel}
我想根据标签是指章节/节/小节（默认编号）还是小节/段落（默认未编号）来生成不同的文本。
我该如何检查？以下两种方法均可：
- 检查标签是否引用章节/节/小节（或相反：检查标签是否引用小节/段落）
- 检查标签是否指向编号商品
答案1
unnumbered/numbered请参阅最后的更新以了解结构单元的引用和检查。
不使用任何额外的包，只\renewcommand, \let, \pdfstrcmp使用等并将写入\@namedef文件.aux。
它需要两次运行（无论如何都是需要的，因为我们正在处理标签！）
使用\extractlabeltype{labelname}与\checklabeltype真/假分支。
它假定没有其他包涉及\label和\ref，即不支持hyperref或。cleveref
\documentclass{book}
\makeatletter
\let\latex@@refstepcounter\refstepcounter
\let\latex@@label\label%
\renewcommand{\refstepcounter}[1]{%
\gdef\lastrefsteppedcounter{#1}%
\latex@@refstepcounter{#1}%
}
\renewcommand{\label}[1]{%
\immediate\write\@auxout{\string\global\string\@namedef{label#1}{\lastrefsteppedcounter}}
\latex@@label{#1}%
}
\newcommand{\extractlabeltype}[1]{%
\@nameuse{label#1}%
}
\makeatother
\newcommand{\checklabeltype}[4]{%
\ifnum0=\pdfstrcmp{\extractlabeltype{#1}}{#2}
#3%
\else
#4%
\fi
}
\begin{document}
\chapter{Foo} \label{foo}
\section{Foosection}\label{foosection}
\checklabeltype{foosection}{section}{Yes, it is section}{No, it is something different}
\checklabeltype{foo}{section}{Yes, it is section}{No, it is something different}
\end{document}
更新检查未编号/已编号的问题。
请注意，这故意依赖于这样的假设：未编号结构单元的锚点名称中包含一个*，因此玩弄\theH...宏并不是一个好主意；-)
\documentclass{book}
\usepackage{xparse}
\usepackage[hyperref,counter]{zref}% Using the counter mechanism behind `nameref`
\usepackage{hyperref}
\makeatletter
\AtBeginDocument{%
\let\latex@@label\label%
\renewcommand{\label}[1]{%
\zref@label{#1}%
\latex@@label{#1}%
}
% Get the underlying counter type
\newcommand{\extractlabelcounter}[1]{%
\zref@ifrefundefined{#1}{%
???????}{%
\zref@extract{#1}{counter}%
}%
}
% Get the anchor name for hyperref or nameref -> has a `*` inside if it is unnumbered
\newcommand{\extractlabelanchor}[1]{%
\zref@ifrefundefined{#1}{%
???????}{%
\zref@extract{#1}{anchor}%
}%
}
}
% Check if there's a `*` inside of the anchor name
\ExplSyntaxOn
\cs_new:Npn \checkifnumbered#1#2#3{%
\tl_set:Nx \l_tmpa_tl {\extractlabelanchor{#1}}
\tl_if_in:NnTF \l_tmpa_tl {*} {#2} {#3}
}
\ExplSyntaxOff
\makeatother
\newcommand{\checklabeltype}[4]{%
\ifnum0=\pdfstrcmp{\extractlabelcounter{#1}}{#2}
#3%
\else
#4%
\fi
}
\begin{document}
\chapter{Foo} \label{foo}
\section*{An unnumbered section} \label{unnumbered}
\section{Foosection}\label{foosection}
\checklabeltype{foosection}{section}{Yes, it is section}{No, it is something different}
\checklabeltype{foo}{section}{Yes, it is section}{No, it is something different}
\begin{enumerate}
\item First \label{enumfirst}
\item Second \label{enumsecond}
\end{enumerate}
\checklabeltype{enumsecond}{enumi}{It is a numbered item and has the value \ref{enumsecond}}{}
In \nameref{unnumbered} we have an \checkifnumbered{unnumbered}{unnumbered}{numbered} \extractlabelcounter{unnumbered}
In \nameref{foo} we have an \checkifnumbered{foo}{unnumbered}{numbered} \extractlabelcounter{foo} whereas
\nameref{foosection} is a \checkifnumbered{foosection}{unnumbered}{numbered} \extractlabelcounter{foosection}.
\end{document}
