我有一份文档，其中章节标题很长，跨越多行（可能是考试题目）。我想将它们限制在目录中的一行内。
我刚刚发现，通过提供一个简短的标题，例如，可以很容易地手动实现这\subsection[Short Title]{Title}一点。但是，我想使这一过程自动化。我非常确定，重新定义\subsection等操作很容易，可以自动设置相应的简短标题，只是我自己还不够熟练，无法想出这个办法。
例子：
\documentclass{article}
\begin{document}
\tableofcontents
\section{What I have}
\subsection{This is an insanely long subsection title that is supposed to span multiple lines, which it does because it's insanely long}
\subsubsection{This is a similarly long subsubsection title that should also span more than one line, which it does as it's very long}
\section{What I want}
\subsection[This is an insanely long subsection title that is supposed to span\ldots]{This is an insanely long subsection title that is supposed to span multiple lines, which it does because it's insanely long}
\subsubsection[This is a similarly long subsubsection title that should\ldots]{This is a similarly long subsubsection title that should also span more than one line, which it does as it's very long}
\end{document}
理想情况下，目录中的标题会自动按单词截断，以便它们刚好适合一行，但具有固定宽度甚至固定字符数的解决方案也可以。
奖励要求：我还为标题着色以指示相应部分的状态，也就是说，如果有一个解决方案也能适用于包装的标题\textcolor{...}{...}（或允许通过可选参数等设置颜色），那就太好了。
答案1
此解决方案使用虚拟保护令牌\splithere从其余部分标题中获取 ToC 材料：
\documentclass{article}
\makeatletter
\def\DefSplitSection#1#2{%
\def#1{\split@startsection#2}%
}
\def\split@startsection#1#2{%
\split@section@aux#1#2\splithere\@nil
}
\def\split@section@aux#1#2\splithere#3\@nil{%
\if\relax\detokenize{#3}\relax
\expandafter\@firstoftwo
\else
\expandafter\@secondoftwo
\fi
{#1{#2}}%
{#1[#2]{#2#3}}%
}
\let\splithere\@empty
\makeatother
\DefSplitSection\splitsection\section
\DefSplitSection\splitsubsection\subsection
\DefSplitSection\splitsubsubsection\subsubsection
\begin{document}
\tableofcontents
\section{What I have}
\splitsubsection{This is an insanely long subsection title that is supposed to span \splithere multiple lines, which it does because it's insanely long}
\splitsubsubsection{This is a similarly long subsubsection title that should \splithere also span more than one line, which it does as it's very long}
\section{What I want}
\subsection[This is an insanely long subsection title that is supposed to span\ldots]{This is an insanely long subsection title that is supposed to span multiple lines, which it does because it's insanely long}
\subsubsection[This is a similarly long subsubsection title that should\ldots]{This is a similarly long subsubsection title that should also span more than one line, which it does as it's very long}
\end{document}
如果使用 no，\splithere则行为与标准分段命令相同。请注意，此变体不适用于可选项*（这毫无意义，因为此变体不会写入 ToC），也不适用于可选[...]参数（同样毫无意义，因为它已经在内部定义了可选参数）。
编辑：在可选参数中支持颜色：
\documentclass{article}
\usepackage{xcolor}
\makeatletter
\def\DefSplitSection#1#2{%
\def#1{\split@startsection#2}%
}
\def\split@startsection#1{%
\let\split@color@cmd\@empty
\@ifnextchar[%]
{\split@color@startsection#1}%
{\split@actually@startsection#1}%
}
\def\split@color@startsection#1[#2]{%
\def\split@color@cmd{\color{#2}}%
\split@actually@startsection#1%
}
\def\split@actually@startsection#1#2{%
\split@section@aux#1#2\splithere\@nil
}
\def\split@section@aux#1#2\splithere#3\@nil{%
\if\relax\detokenize{#3}\relax
\expandafter\@firstoftwo
\else
\expandafter\@secondoftwo
\fi
{#1{\split@color@cmd#2}}%
{#1[\split@color@cmd#2]{\split@color@cmd#2#3}}%
}
\let\splithere\@empty
\makeatother
\DefSplitSection\splitsection\section
\DefSplitSection\splitsubsection\subsection
\DefSplitSection\splitsubsubsection\subsubsection
\begin{document}
\tableofcontents
\section{What I have}
\splitsubsection[blue]{This is an insanely long subsection title that is supposed to span \splithere multiple lines, which it does because it's insanely long}
\splitsubsubsection{This is a similarly long subsubsection title that should \splithere also span more than one line, which it does as it's very long}
\section{What I want}
\subsection[This is an insanely long subsection title that is supposed to span\ldots]{This is an insanely long subsection title that is supposed to span multiple lines, which it does because it's insanely long}
\subsubsection[This is a similarly long subsubsection title that should\ldots]{This is a similarly long subsubsection title that should also span more than one line, which it does as it's very long}
\end{document}