How to get the current chapter* name, section* name, subsection* name, etc?

Question

I came across this answer which claims that it works even with the starred version of \chapter et al. The following example shows that it does not, because \...mark macros are not called. Is there a way to "fix" this and be able to set the respective value of the \...name macros even if there is a *-type call?

\documentclass{book}

\let\Chaptermark\chaptermark
\let\Sectionmark\sectionmark
\let\Subsectionmark\subsectionmark
\let\Subsubsectionmark\subsubsectionmark
\def\chaptermark#1{\def\Chaptername{#1}\Chaptermark{#1}}
\def\sectionmark#1{\def\Sectionname{#1}\Sectionmark{#1}}
\def\subsectionmark#1{\def\Subsectionname{#1}\Subsectionmark{#1}}
\def\subsubsectionmark#1{\def\Subsubsectionname{#1}\Subsubsectionmark{#1}}

\begin{document}
\chapter{First chapter}
Title: ``\Chaptername''.
\section{First section}
Title: ``\Sectionname''.
\subsection{First subsection}
Title: ``\Subsectionname''.
\subsubsection{First subsubsection}
Title: ``\Subsubsectionname''.
\chapter*{Second chapter}
Title: ``\Chaptername''.
\section*{Second section}
Title: ``\Sectionname''.
\subsection*{Second subsection}
Title: ``\Subsectionname''.
\subsubsection*{Second subsubsection}
Title: ``\Subsubsectionname''.
\end{document}

Lets assume that I have a long file with many \section (etc.) calls. But there is a macro which I want to change to contain the title of the actual section (etc.).

Answer 1

The given macros will not work with the *-versions, because the \...mark commands are issued only when the * is not present. For instance, \chapter{Title} issues \chaptermark{Title}, but \chapter*{Title} doesn't.

Here's a set of patches that will provide the commands

\chaptertitle
\sectiontitle
\subsectiontitle
\subsubsectiontitle

which will always expand to the most recent title of the corresponding sectional unit.

\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
% \@sect is called with normal sectioning commands
% Argument #8 to \@sect is the title
% Thus \section{Title} will do \gdef\sectiontitle{Title}
\pretocmd{\@sect}
  {\expandafter\gdef\leveltitle{#8}}
  {}{}
% \@ssect is called with *-sectioning commands
% Argument #5 to \@ssect is the title
\pretocmd{\@ssect}
  {\expandafter\gdef\leveltitle{#5}}
  {}{}
% \@chapter is called by \chapter (without *)
% Argument #2 to \@chapter is the title
\pretocmd{\@chapter}
  {\expandafter\gdef\leveltitle{#2}}
  {}{}
% \@schapter is called with \chapter*
% Argument #1 to \@schapter is the title
\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}

Here \test is just to show that at the point the command is issued the control sequences hold the right value.

The patches must go before the loading of hyperref (if you use it).