Accessing chapter's name in Koma-Script

Question

I looked up for a solution to access the name of current sections (chapters, sections, etc.) from macros (including starred variations of the section command). The set of macros proposed here works like a charm in the base class book.

\documentclass{book}

\usepackage{etoolbox}
% Patch the sectioning commands to provide a hook to be used later
\preto{\chapter}{\def\leveltitle{\chaptertitle}}
\preto{\section}{\def\leveltitle{\sectiontitle}}
\preto{\subsection}{\def\leveltitle{\subsectiontitle}}
\preto{\subsubsection}{\def\leveltitle{\subsubsectiontitle}}

\makeatletter
\pretocmd{\@sect}
  {\expandafter\gdef\leveltitle{#8}}
  {}{}
\pretocmd{\@ssect}
  {\expandafter\gdef\leveltitle{#5}}
  {}{}
\pretocmd{\@chapter}
  {\expandafter\gdef\leveltitle{#2}}
  {}{}
\pretocmd{\@schapter}
  {\expandafter\gdef\leveltitle{#1}}
  {}{}
\makeatother

\newcommand\test{%
  \noindent
  The chapter title is \chaptertitle\\
  The section title is \sectiontitle\\
  The subsection title is \subsectiontitle\\
  The subsubsection title is \subsubsectiontitle
}

\begin{document}
\chapter{First chapter}
\section{First section}
\subsection{First subsection}
\subsubsection{First subsubsection}

\test

\chapter*{Second chapter}
\section*{Second section}
\subsection*{Second subsection}
\subsubsection*{Second subsubsection}

\test
\end{document}

However I need to implement my macros in Koma-Script, with scrbook and here things start to get unexpected. With the same code but with class scrbook I get the following:

The chapter name is not rendered. I looked up the code of scrbook and the title is indeed #2. Is there something wrong with the macros and how to fix this issue?

For my needs, it is not possible to use nameref, I need a hard-coded solution. Thanks for you help.

Bonus: Is it possible to choose between long titles and short titles (the ones defined with \section[short]{long}? Thanks again.

Answer 1

You can use nameref, all you need is an automatically set \label and a the name of the current label. From upcomming KOMA-Script 3.27 (currently only available from the KOMA-Script source repository or the KOMA-Script pre-release repository) the new do-hook feature can be used to add the automatic labels:

\documentclass[headings=optiontoheadandtoc]{scrbook}[2019/03/05]
\usepackage{nameref}
\newcounter{secautolabel}
\AddtoDoHook{heading/endgroup}{\setautolabel}
\newcommand*{\setautolabel}[1]{%
  \stepcounter{secautolabel}%
  \label{sec:autolabel:\thesecautolabel}%
  \expandafter\xdef\csname #1title\endcsname{%
    \noexpand\nameref{sec:autolabel:\thesecautolabel}%
  }%
}

\newcommand\test{%
  \noindent
  The chapter title is \chaptertitle\\
  The section title is \sectiontitle\\
  The subsection title is \subsectiontitle\\
  The subsubsection title is \subsubsectiontitle
}

\begin{document}
\chapter{First chapter}
\section{First section}
\subsection[reference={The First subsection reference}]{First subsection}
\subsubsection{First subsubsection}

\test

\chapter*{Second chapter}
\section*{Second section}
\subsection*{Second subsection}
\subsubsection*{Second subsubsection}

\test
\end{document}

with the results:

So you do not need to patch or use (internal) commands.

With the current official release you can do something similar by patching \sectionlinesformat and \chapterlinesformat:

\documentclass[headings=optiontoheadandtoc]{scrbook}
\usepackage{nameref}
\newcounter{secautolabel}
\newcommand*{\setautolabel}[1]{%
  \stepcounter{secautolabel}%
  \label{sec:autolabel:\thesecautolabel}%
  \expandafter\xdef\csname #1title\endcsname{%
    \noexpand\nameref{sec:autolabel:\thesecautolabel}%
  }%
}
\usepackage{xpatch}
\xapptocmd{\sectionlinesformat}{\setautolabel{#1}}{}{\undefined}
\xapptocmd{\sectioncatchphraseformat}{\setautolabel{#1}}{}{\undefined}
\xapptocmd{\chapterlinesformat}{\setautolabel{#1}}{}{\undefined}
\xapptocmd{\chapterlineswithprefixformat}{\setautolabel{#1}}{}{\undefined}

\newcommand\test{%
  \noindent
  The chapter title is \chaptertitle\\
  The section title is \sectiontitle\\
  The subsection title is \subsectiontitle\\
  The subsubsection title is \subsubsectiontitle
}

\begin{document}
\chapter{First chapter}
\section{First section}
\subsection[reference={The First subsection reference}]{First subsection}
\subsubsection{First subsubsection}

\test

\chapter*{Second chapter}
\section*{Second section}
\subsection*{Second subsection}
\subsubsection*{Second subsubsection}

\test
\end{document}

The result is the same as above.

BTW: In both examples I've shown, how to manipulate the result using option headings=optiontotocandhead and the extended optional argument of, e.g., \subsection.