I'm aware that using package titletoc one can easily change the format of ToC. But, I'm wondering if there exist some solutions to make the left margin in ToC flexible. By "flexible", I mean that the left margin of certian level will change according to the current label number. For example, if there exist a \chapter, but no \section, \subsection and \subsubsection, then an immediate \paragraph will have the same margin in TC as the normal \section. I know that the margin of a section title is basically controlled by the <left> option in titletoc package. So my naive idea is to combine this with some \ifthenelse.
\documentclass{book}
\usepackage{xifthen}
\usepackage{titletoc}
\setcounter{tocdepth}{4}
\setcounter{secnumdepth}{4}
\newlength{\TOCparagraphskip}
\setlength{\TOCparagraphskip}{9em}
\titlecontents*
{paragraph}
[\ifnum\pdfmatch{.[.].[.].[.]0[.].}{\thecontentslabel}=1
\setlength{\TOCparagraphskip}{7em}%
\ifnum\pdfmatch{.[.].[.]0[.]0[.].}{\thecontentslabel}=1
\setlength{\TOCparagraphskip}{3.8em}%
\ifnum\pdfmatch{.[.]0[.]0[.]0[.].}{\thecontentslabel}=1
\setlength{\TOCparagraphskip}{1.5em}%
\ifnum\pdfmatch{0[.]0[.]0[.]0[.].}{\thecontentslabel}=1
\setlength{\TOCparagraphskip}{0em}%
\fi
\fi
\fi
\else
\setlength{\TOCparagraphskip}{9em}%
\fi
\TOCparagraphskip]{}{\textbullet{}\;}{}{}[\quad]
\begin{document}
\tableofcontents
\paragraph{paragraph}
\chapter{chapter one}
\end{document}
But, unfortunately, my naive try give error message.
(./test.toc
./test.toc:1: Missing number, treated as zero.
<to be read again>
\protect
l.1 ...aph}{\numberline {0.0.0.0.1}paragraph}{1}{}
%
A number should have been here; I inserted `0'.
(If you can't figure out why I needed to see a number,
look up `weird error' in the index to The TeXbook.)
./test.toc:1: Illegal unit of measure (pt inserted).
<to be read again>
\protect
l.1 ...aph}{\numberline {0.0.0.0.1}paragraph}{1}{}
%
Dimensions can be in units of em, ex, in, pt, pc,
cm, mm, dd, cc, nd, nc, bp, or sp; but yours is a new one!
I'll assume that you meant to say pt, for printer's points.
To recover gracefully from this error, it's best to
delete the erroneous units; e.g., type `2' to delete
two letters. (See Chapter 27 of The TeXbook.)
./test.toc:1: Package calc Error: `\let ' invalid at this point.
See the calc package documentation for explanation.
Type H <return> for immediate help.
...
l.1 ...aph}{\numberline {0.0.0.0.1}paragraph}{1}{}
%
I expected to see one of: + - * / )
But I've checked that with or without my personal hack, the .toc file are in fact the same.
\contentsline {paragraph}{\numberline {0.0.0.0.1}paragraph}{1}{}%
\contentsline {chapter}{\numberline {1}chapter one}{3}{}%
\contentsfinish
So, I don't know where is the problem. Or, maybe someone else has some better idea to implement this functionality?
Best Answer
Here's how I would implement what you want instead.
Basic example:
You see that but inserting various
\setlengthinto the toc file you can change the left indent on the fly.Now let's try to automate it. Unfortunately the
<after code>intitlesecdoesn't work because it results in the contents line being printed too early. However, trying to useetoolboxto append code to run after sectioning commands is prone to unexpected errors.In the solution below, what we do is the following:
\paragraphcommand so that before the normal\paragraphis called, we check to see if the indentation needs changing. If it does, then we issue an\addtocontentsto do so.\addtocontents, we reset the toggle.*forms or other shenanigans. I did it by hand below, but I think using the\pretocmdmacro frometoolboxwould work just as well.\chapter,\section,\subsection, and so on; I got tired of typing so you have to add the additional levels yourself) to indicate that the indentation level has changed, and store the appropriate lengths.\paragraphis called the right length is placed in the.tocfile..tocfile down (otherwise you print one\setlengthcommand for each\paragraph). In the example below it would be 7 times without the toggle, and 5 times with the toggle.The output TOC from the code above: