# How to put a star (or other symbol) in sections that are “special” (difficult, optional, etc)?

I'm currently writing a book, and I'd like some of the sections to be clearly marked as "difficult" or "optional". Not only sections, but also exercises (I'm using the exercise package) and theorems (that I am defining with newtheorem from amsthm)). Something that would work for arbitrary sectioning levels, environments, etc would be great...

edit: I think I should have also said -- I'd like something like a star at the margin, close to the section/theorem/etc, and, if it's a section or chapter, then there should be a star before it in the text and at the table of contents:

1 Introduction
1.1 blah
2.3 blah
2 Some Chapter
2.1 blah
* 2.2 this is an optional section
2.3 blah blah


edit: it would be nice if the star (or a configurable symbol of course) was placed before the section number.

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The titletoc manual introduces an interesting method to do what you are after. It's illustrated best with an example.

\documentclass[11pt,a4paper,english]{book}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{babel}
\usepackage[pagestyles,raggedright]{titlesec}
\usepackage{titletoc}
\usepackage{blindtext}

\author{Jay}

\newcommand{\secmark}{}
\renewcommand{\secmark}{*}%
}

\titleformat{\section}{\normalfont\Large}{\makebox[1.5em][l]{\llap{\secmark}\thesection}}{0.4em}{}
\titlecontents{section}[3.7em]{}{\contentslabel[\llap{\secmark}\thecontentslabel]{2.3em}}{\hspace*{-2.3em}}{\titlerule*{}\bfseries\contentspage}

\newpagestyle{front}{%
\setfoot[][][]{}{}{}
}

\newpagestyle{main}{%
\setfoot[][][]{}{}{}
}
\newpagestyle{back}{%
\setfoot[][][]{}{}{}
}

\begin{document}
\frontmatter
\pagestyle{front}
\maketitle
\tableofcontents\newpage

\mainmatter
\pagestyle{main}
\blinddocument
\blinddocument
\blinddocument

\backmatter
\appendix
\pagestyle{back}
\end{document}


This example starts with marking selected sections within a chapter. For marked chapters it needs to be modified accordingly.

As always, the blindtext package is only for creating dummy text, thus is not part of the solution.

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Thank you! Now I can also declare \newcommand{\advsection}[1]{\begin{advanced}\section{#1}\end{advanced}}, which gives me a nice \advsection command. :-) –  Jay Jun 19 '12 at 2:42

I don't have an answer for sections, but I do have one for environments. It allows you to tag the environments you want labelled specially.

\documentclass{article}
\usepackage{ifthen}
\usepackage{xargs}
\usepackage{lipsum}

\setlength{\parindent}{0mm}

\newcounter{problem}
\newcommand{\trickysymbol}{$\clubsuit$ }
\newlength{\trickysymbollength}
\settowidth{\trickysymbollength}{\trickysymbol}
\newenvironmentx{problem}[2][1={},2={},usedefault]{%
\refstepcounter{problem}%
\ifthenelse{\equal{#2}{}}%
{%
% if no second argument
\ifthenelse{\equal{#1}{}}%
{%
\textbf{Problem \theproblem }\par%
}%
{%
\textbf{Problem \theproblem \, (#1) }\par%
}%
}%
{%
% tricky problems
\ifthenelse{\equal{#2}{tricky}}%
{%
\ifthenelse{\equal{#1}{}}%
{%
\hspace{-\trickysymbollength}\trickysymbol\textbf{Problem \theproblem }\par%
}%
{%
\hspace{-\trickysymbollength}\trickysymbol\textbf{Problem \theproblem \, (#1) }\par%
}%
}{ \textbf{Problem} \theproblem \, (#1) {\bf\huge\color{red}tricky?}\par}%
}%
\ignorespaces%
}%
{%
\par\noindent\ignorespacesafterend
}%

\begin{document}

\begin{problem}[description goes here]
\lipsum[1]
\end{problem}

\begin{problem}[description goes here][tricky]
\lipsum[1]
\end{problem}

\begin{problem}[][tricky]
\lipsum[1]
\end{problem}

\end{document}

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Hey, that works great for environments - thanks! Now I only need the same for sections (and chapters, perhaps) -- with the same symbol appearing by the section in the text and also before it in the table of contents... –  Jay Jul 27 '11 at 13:40
You're welcome! Looks like some of the other folk have answers for the sections- good luck! –  cmhughes Jul 27 '11 at 16:27

I wouldn't use a symbol in section, I would define a command.

Example:

\documentclass[11pt]{scrartcl}
%\Section with capital S for important sections
\newcommand{\Section}[1]{\section[! #1]{(Important) #1}}
%\newcommand{\Section}[1]{\section[#1\hfill!]{(Important) #1}}

\begin{document}
\tableofcontents
\section{First section}
\Section{Second section}

\end{document}


Instead of Section you may use ImportantSection or OptionalSection... So you get a clear markup.

Modified example with optional parameters:

\documentclass[11pt]{scrartcl}
\usepackage{color}
\definecolor{optionalgray}{gray}{.75}

\makeatletter
\newcommand\@ImportantSection[2][]{
%Define the look of Important sections
\section[#1 (!)]{(*) #2}
%\section[#1 (!)]{\textcolor{red}{#2}}
}
\newcommand\ImportantSection{\@dblarg\@ImportantSection}

\newcommand\@OptionalSection[2][]{
%Define the look of Optional sections
\section[#1 (!)]{(#2)}
%\section[#1 (!)]{\textcolor{optionalgray}{#2}}
}
\newcommand\OptionalSection{\@dblarg\@OptionalSection}
\makeatother

\begin{document}
\tableofcontents
\section{First section}
\ImportantSection{Second section}

\ImportantSection[3rd]{Third section}

\OptionalSection[4th]{Fourth section}

\end{document}

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Thank you -- but I'd rather use a symbol (a simple star), as it makes it easier for the reader to spot difficult sections or theorems, etc, and uses less space (some section names are a bit long already). –  Jay Jul 26 '11 at 19:15
Perhaps I misunderstood you. I expected you want to define macros like \section! and a redefinition \section*. There I recommend to use more explicit macros like \ImportantSection. In your comment you write about the reader. Should the symbol to be a part in your LaTeX-Input or in the output? Then take a look in my modified example. There I set a (*) for important sections and optional section are in (). You may define your own look. –  knut Jul 26 '11 at 19:34

This is similar to a problem I had, so use something like

\DeclareRobustCommand{\SymbolInRed}{$\textcolor{red}{\times}$}


and then use this symbol in the section as:

\section{Second Chapter\SymbolInRed}


See Undefined color error, if have symbol in Chapter Title for more info on this.

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As for adding stars to the toc then this might help (as long as it is numbered, in which case the with of the number part is in \@tempdima)

\documentclass[a4paper]{article}
\usepackage{etoolbox}
\newtoggle{activestar}
\makeatletter
\DeclareRobustCommand\mystar{%
\iftoggle{activestar}{%
\llap{$*$\kern0.2em\kern\@tempdima}%
}{}%
\ignorespaces
}
\makeatother
\begin{document}
\toggletrue{activestar}
\tableofcontents
\togglefalse{activestar}

\section{\mystar{}Test}
\section{Test}
\end{document}


Of course it would be recommend to define a \specialsection or similar as other have mentioned.

As for marking in the text, it might be more helpful to the reader if the author used a marginal note to specify that this is special.

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