Adding a \ref to a counter? - comp.text.tex

Message from discussion Adding a \ref to a counter?

Heiko Oberdiek

More options Apr 8 1998, 3:00 am

Newsgroups: comp.text.tex

From: oberd...@ruf.uni-freiburg.de (Heiko Oberdiek)

Date: 1998/04/08

Subject: Re: Adding a \ref to a counter?

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Jon Haugsand <haugs...@regulus.nr.no> wrote:
>In a humble attempt to simulate a spreadsheet in LaTeX, I tried to add
>a \ref to a counter like this:

>\newcounter{bbb}\setcounter{bbb}{50}\addtocounter{bbb}{\ref{AAA}}
>(\thebbb)
>...
>\newcounter{aaa}\setcounter{aaa}{100}\refstepcounter{aaa}\label{AAA}

>This did not work out as \ref{AAA} is not a number. Is it possible to
>coerce it into a number? Or maybe redefine \ref and \label to also
>save numbers?

In a thread in de.comp.text.tex I have written commands to convert
\ref into a number. Here the next version as a package file:

--- snip --- 'refcount.sty' --- snip --- begin ---
% refcount.sty
% (c) Copyright 1998 by Heiko Oberdiek.
%
% User interface
%
% eg: \newcounter{CNTR}
% \refstepcounter{CNTR}\label{REF}
%
% * \setcounterwithref{CounterTwo}{REF}
% * \addtocounterwithref{CounterTwo}{REF}
%
% Hints
%
% * The \label-command should store the reference REF of the counter
CNTR
% as an arabic number (\theCNTR ==> \arabic{CNTR}).
% * Zero is assumed for undefined references.
% * Tested with packages 'calc' and 'hyperref'.
%
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{refcount}
[1998/04/08 Use of \ref in counter commands]

\newcommand{\@FirstParam}{}
\def\@FirstParam#1#2\END{#1}

\newcommand{\@useref}[3]{%
\begingroup
\expandafter\let\expandafter\refcmd\csname r@#3\endcsname
\ifx\refcmd\relax
\PackageWarning{refcount}{Undefined reference '#3'}%
#1{#2}{0}%
\else
#1{#2}{\expandafter\@FirstParam\refcmd\END}%
\fi
\endgroup

}

\newcommand{\setcounterwithref}[2]{%
\@useref\setcounter{#1}{#2}%

}

\newcommand{\addtocounterwithref}[2]{%
\@useref\addtocounter{#1}{#2}%

}

\endinput
--- snip --- 'refcount.sty' --- snip --- end ---

Your example looks now:

--- snip --- 'test.tex' --- snip --- end ---
\documentclass{article}}
%\usepackage{calc}
%\usepackage{hyperref}
\usepackage{refcount}

\newcounter{aaa}
\newcounter{bbb}

\begin{document}
\setcounter{bbb}{50}\addtocounterwithref{bbb}{AAA}
(\thebbb)

\setcounter{aaa}{-100}\refstepcounter{aaa}\label{AAA}

\end{document}
--- snip --- 'test.tex' --- snip --- end ---

Yours sincerely
Heiko <oberd...@ruf.uni-freiburg.de>

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