Automatically create table with stored content

Question

I have a rather long file with certain information about topics (say, name of the topics and tags associated to it). I want to get an automatic table at the beginning of my document that summarizes this information (somewhat similar to a toc) in the following way: First column is the topic, second are the provided tags, third is the page where the topic is listed.

I want to achieve this through commands (say, \topic and \tags), that I use when starting the new topic and I want LaTeX to produce the table automatically, using the information gathered in all these commands.

Does anyone know how this can be done?

[No MWE provided since I don't even know how to start. I found it kind of hard to explain what I want to achieve, if it is not clear I can try to make it clearer.]

EDIT:

I will try to clarify what I want. In the following code

\documentclass{scrartcl}
\begin{document}
\begin{tabular}{lll}
Topic & Tags & Page \\
Topic 1 & A,B,C & 2 \\
Topic 2 & D,E & 3 \\
Topic 3 & A,E & 4
\end{tabular}
\newpage
Topic 1 \\ Tags A,B,C \newpage
Topic 2 \\ Tags D,E \newpage
Topic 3 \\ Tags A,E
\end{document}

I have three topics, each on a new page, with certain tags. On the first page I have a table that summarizes all topics that occur. I now want to have commands, say \topic,\tag, such that I can use \topic{Topic 1} and \tag{A,B,C} when Topic 1 starts, so that the respective row in the table will created automatically (and I don't have to put in the table manually at all).

EDIT 2: Maybe it is possible to adapt the code of the \newlistof command from the tocloft package to create a table (instead of a list), but I don't understand that well enough to do so.

Answer 1

I am not sure, if I understand, what you want to do. But maybe, the following helps a bit.

\documentclass[headings=optiontoheadandtoc]{scrartcl}
\usepackage{lipsum}% only for dummy text

\DeclareRobustCommand*{\tags}[1]{{\normalfont\mbox{(#1)}}}

\DeclareRobustCommand*{\listoftopicsfirstline}{%
  {\usekomafont{sectionentry}{Topics} {\normalfont(Tags)} \hfill {\usekomafont{sectionentrypagenumber}{Page}}}\par
}
\addtocontents{toc}{\listoftopicsfirstline}
\defcaptionname{english}{\contentsname}{List of Topics}

\begin{document}
\tableofcontents

\addsec
  [tocentry={Topic 1 \tags{A,B,C}}]
  {Topic 1}
\lipsum[1-20]

\addsec
  [tocentry={Topic 2 \tags{D,E}}]
  {Topic 2}
\lipsum[1-20]

\addsec
  [tocentry={Longer Topic 3 \tags{A,E}}]
  {Topic 3}
\end{document}