I would like to make visual table of contents, just like here. However, I have a part that does not have a section and I would like it to output, but it does not do so.
I took my code from here as well and deleted the sections for the last part (\part {Model-building Methods}):
\documentclass[12pt,oneside, tikz, ignorerest=false]{standalone}
\usepackage{tikz}
\usetikzlibrary{mindmap}
\pagestyle{empty}
\usepackage{etoc}
% \usepackage{hyperref}% if links are wanted
\begin{document}
\newtoks\treetok
\newtoks\parttok
\newtoks\sectiontok
\newcommand*\treenode {} % just to check we don't overwrite something
\newcommand*\tmprotate {} % just to check we don't overwrite something
\newcommand*\tmpoption {} % just to check we don't overwrite something
\newcommand*\tmpstuff {} % just to check we don't overwrite something
\newcommand*\appendtotok[2]{% #1=toks variable, #2=macro, expands once #2
#1\expandafter\expandafter\expandafter{\expandafter\the\expandafter #1#2}}
\newcommand*{\appendchildtree}[3]{%
% this is to construct "t1 child [concept color= #3]{t2}" from #1=t1 and #2=t2
% t1 and t2 are two toks variable (not macros)
% #3 = for example teal!60
\edef\tmpstuff {\the#1 child [concept color = #3]{\the#2}}%
#1\expandafter {\tmpstuff }%
}
\newcounter{partco}
\etocsetstyle{part}
{}
{}
{\toks0 \expandafter{\etocthelinkednumber}%
\toks2 \expandafter{\etocthelinkedname }%
\stepcounter{partco}%
\ifcase\value{partco}%
\or \def\tmpoption {}%
\def\tmprotate {}% first
\or \def\tmpoption {[concept]}%
\def\tmprotate {[clockwise from = 60]}% second
\else\def\tmpoption {}%
\def\tmprotate {[counterclockwise from = 90]}% third and higher
\fi
% define the part node
\edef\treenode{node \tmpoption {\the\toks0. \the\toks2} \tmprotate }%
% this is a starting point which will be filled it by the section children
\parttok\expandafter{\treenode}}
{}
\etocsetstyle{section}
{}
{}
{\toks0 \expandafter{\etocthelinkednumber}%
\toks2 \expandafter{\etocthelinkedname }%
% define the section node
\edef\treenode {node {\the\toks0 \space\the\toks2}}
\sectiontok\expandafter{\treenode}%
% update current part tree with this section node, adding the correct color
\ifcase\value{partco}%
\or \appendchildtree\parttok\sectiontok {teal!30}% first
\or \appendchildtree\parttok\sectiontok {yellow!40}% second
\else\appendchildtree\parttok\sectiontok {green!30}% third etc...
\fi }
% This updates the global tree with the data from the
% part and all its children sections
{\ifcase\value{partco}%
\or \appendchildtree\treetok\parttok {teal!60}% first
\or \appendchildtree\treetok\parttok {yellow!80}% second
\else\appendchildtree\treetok\parttok {green!50}% third and next ...
\fi
}
\etocsettocstyle
{\treetok{\node{\textbf{Discrete Data Analysis with R}} [clockwise from=60]}}
{\global\appendtotok\treetok{ ;}}
% The \global above is mandatory because etoc always typesets TOC inside a group
\tableofcontents
% \showthe\treetok % debugging
\begin{tikzpicture}[grow cyclic, text width=2cm,
align=flush center,
every node/.style=concept,
concept color=orange!60,
level 1/.style={level distance=7cm,sibling angle=120},
level 2/.style={level distance=4cm,sibling angle=45}]
\the\treetok
\end{tikzpicture}
\part {Getting Started}
\section {Introduction}
\section {Working with Categorical Data}
\section {Discrete Distributions}
\part {Exploratory Methods}
\section {Two-way Contingency Tables}
\section {Mosaic Displays}
\section {Correspondence Analysis}
\part {Model-building Methods}
\end{document}
The code above produces the image below. However, as you can see, the part Model-building Methods is not outputted in the image.
I would like to output the part ''Model-building Methods'' as well, even though it doesn't contain sections. How can I do this?
Thanks in advance.

