Reverse numeration

Question

I would like to find a solution to generate items with a reverse counting of the numbering like this

Blablabla
Blablabla
Blablabla

Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking. — Community, Jun 29 '22 at 14:09
The counting in your example is not reversed. But does not begin with 1. Please clarify what you wish to achieve. — Ulrich Diez, Jun 29 '22 at 14:12

Ulrich Diez · Answer 1 · 2022-06-29T16:23:58.390

Perhaps something like this does the trick—it requires at least two compilations to work out:

\documentclass{article}
\usepackage[colorlinks=true]{hyperref}
\usepackage[user]{zref}
\makeatletter
\zref@newprop{ItemNo}{}%
\newcommand\my@caseselect[2]{#2}%
\newcommand\ItemNumberlabel[1]{%
  \bsphack
  \begingroup
  \let\my@caseselect=@firstoftwo
  \zref@setcurrent{ItemNo}{\number\value{enum\romannumeral@enumdepth}}%
  \zref@labelbyprops{#1}{ItemNo}%
  \endgroup
  \esphack
}%
\newcommand\revertcounting[2]{%
  \expandafter@revertcounting
  \expandafter{\romannumeral\the\numexpr@enumdepth+1\expandafter\relax\expandafter}%
  \expandafter{\romannumeral\the@enumdepth}%
  {#1}{#2}%
  \ignorespaces
}%
\newcommand@revertcounting[4]{%
  @namedef{theenum#1}{%
    \my@caseselect{%
      \csname @#4\endcsname{\csname c@enum#1\endcsname}%
    }{%
      \zref@ifrefundefined{#3}%
                          {\csname @#4\endcsname{\csname c@enum#1\endcsname}}%
                          {%
                             \csname @#4\endcsname{%
                               \the\numexpr
                                  \zref@extractdefault{#3}{ItemNo}{0} - %
                                  \number\value{enum#1} + 1%
                                \relax
                             }%
                          }%
    }%
  }%
}%
\makeatother
\begin{document}
\null\par\kern-3cm
\begin{enumerate}
\item text A
\item text B
\item
\begin{enumerate}
\item text One
\item \label{itA}text Two
\item text Three
\item text Four
\end{enumerate}
\item text D
\end{enumerate}
\bigskip\hrule\bigskip
\begingroup
\revertcounting{lastitemA}{arabic}%
\begin{enumerate}
\item text A
\item text B
\item
\begingroup
\revertcounting{lastitemB}{alph}%
\begin{enumerate}
\item text One
\item \label{itB}text Two
\item text Three
\item \ItemNumberlabel{lastitemB}text Four
\end{enumerate}
\endgroup
\item \ItemNumberlabel{lastitemA}text D
\end{enumerate}
\endgroup
\bigskip\hrule\bigskip
\begingroup
\revertcounting{lastitemC}{arabic}%
\begin{enumerate}
\item text A
\item text B
\item
\begin{enumerate}
\item text One
\item \label{itC}text Two
\item text Three
\item text Four
\end{enumerate}
\item \ItemNumberlabel{lastitemC}text D
\end{enumerate}
\endgroup
\bigskip\hrule\bigskip
\begin{enumerate}
\item text A
\item text B
\item
\begingroup
\revertcounting{lastitemD}{alph}%
\begin{enumerate}
\item text One
\item \label{itD}text Two
\item text Three
\item \ItemNumberlabel{lastitemD}text Four
\end{enumerate}
\endgroup
\item text D
\end{enumerate}
Cross-referencing:
\verb|\ref{itA}|: \ref{itA}
\verb|\ref{itB}|: \ref{itB}
\verb|\ref{itC}|: \ref{itC}
\verb|\ref{itD}|: \ref{itD}
\end{document}

Reverse numeration

1 Answers1