How to create a table of contents using tocloft that incorporates levels?

Question

In the same way that creating a standard table of contents makes use of levels (chapters, sections, subsections, etc.) Is there a way to create a custom function that that mimics this using tocloft? I have played around with modifications to #8 in this list of ways to customize toc to get the list of lists effect as well as this more in-depth guide on the behavior of the functions with no luck.

I am envisioning some custom function of the form:

\function{the chapter}{the section} 

Called like this in the code:

\function{pine}{cone}

\function{pine}{wood}

\function{foo}{bar}

Generates a table of contents something like this when \listofWHATEVER is called:

1. Pine

   • cone

   • wood

2. foo

   • bar

I know there are examples of doing this using custom environments or brute-forcing it using enumerate/itemize. But I'm hoping there is some way to do it with a custom command.

I've searched around and haven't seen a solution for this, it's possible I have been using the wrong keywords or simply missed it. Examples or links to a solution would be much appreciated.

Answer 1

A preliminary version without hyperlinking etc. of page numbers.

The code stores the individual keywords and their values in expl3 sequences and writes the values to a .foo ToC file at the end of the document, which is then typeset with \listofwhatever.

The keywords are set with chapter like ToC - entries, the values with section like entries, tocloft is used to disable pagenumbers for the keywords in the .foo file.

\documentclass{book}

\usepackage{xparse}

\newcounter{keyword}
\newcounter{keywordvalue}



\usepackage{tocloft}


\makeatletter
\newcommand{\listofwhatever}{%
  \begingroup
  \clearpage
  \section*{List of Whatever}
  \@starttoc{foo}
  \endgroup
}
\makeatother

\ExplSyntaxOn

\seq_new:N \g_full_keywords_seq

\NewDocumentCommand{\addkeyword}{m}{%
  \seq_if_in:NnF \g_full_keywords_seq {#1} {%
    \seq_new:c {g_#1_local_keywords_seq }
    \seq_new:c {g_#1_local_pagenumber_seq }
  }
  \seq_gput_right:Nn \g_full_keywords_seq {#1}
  \seq_gremove_duplicates:N \g_full_keywords_seq
}

\NewDocumentCommand{\function}{m+m}{%
  \addkeyword{#1}%
  \seq_if_exist:cT {g_#1_local_keywords_seq } {
    \seq_gput_right:cx {g_#1_local_keywords_seq } {#2;;;;;\thepage}
  }
}

\NewDocumentCommand{\generatelistof}{}{%
  \addtocontents{foo}{\protect\renewcommand{\protect\cftsecdotsep}{\cftnodots}}%
  \addtocontents{foo}{\protect\cftpagenumbersoff{chapter}}
  \seq_map_inline:Nn \g_full_keywords_seq {%
    \refstepcounter{keyword}%
    \addcontentsline{foo}{chapter}{\protect\numberline{\thekeyword}##1}%
    \seq_map_inline:cn {g_##1_local_keywords_seq} {%
      \seq_set_split:Nnn \l_tmpa_seq {;;;;;} {####1}
      % Use this without hyperref
      \addtocontents{foo}{\protect\contentsline{section}{\textbullet\protect\quad \seq_item:Nn \l_tmpa_seq {1}}{\seq_item:Nn \l_tmpa_seq {2}}}
      % Use this with hyperref
      %\addtocontents{foo}{\protect\contentsline{section}{\textbullet\protect\quad \seq_item:Nn \l_tmpa_seq {1}}{\seq_item:Nn \l_tmpa_seq {2}}{}{}}
    }
  }
}



\ExplSyntaxOff

\usepackage{blindtext}



\AtEndDocument{%
  \generatelistof
}



\begin{document}
\listofwhatever
\tableofcontents

\chapter{Foo}
\section{Foo section}

\function{pine}{cone}
\function{pine}{wood}

\blindtext[10]
\function{foo}{bar}

\function{pine}{sawmill}

\function{foo}{Hello Darkness my old friend}



\end{document}