Let's get it just right: An \aboveorbelow{some-label} command

Question

I would like to define an \aboveorbelow command which can be used as follows:

\documentclass{article}
\begin{document}
\section{Animals}
\label{sec:animals}
\section{Another section}
The quick brown fox (from \ref{sec:animals} \aboveorbelow{sec:animals})
jumped over the lazy dog.
The quick brown fox (from \ref{sec:plants} \aboveorbelow{sec:plants})
jumped over the lazy dog.
\section{Plants}
\label{sec:plants}
\end{document}

and will produce "above" if the label with identifier equal to the argument appears earlier in the document than the invocation of \aboveorbelow, "below" if it appears later, and something else if it is missing.

How would I do that while properly recognizing intra-page references?

In the related question Referencing to "above" or "below"? two solutions require specific extra-labeling (e.g. with a \here or \location command); another one uses the varioref package, but will apparently fail for labels on the same page as the reference. I would rather use existing labels without having to create new ones, and preferably without having to patch the label command with etoolbox or anything like that.

@DavidCarlisle: I've been using \autoref rather than \ref for so long I tend to forget it's a hyperref command. Edited. — einpoklum, Mar 08 '18 at 21:42
if you had provided a test file (still not done) there would be nothing to remember as then you can easily check that the file runs. — David Carlisle, Mar 08 '18 at 22:39
thanks, it really does help (not for this question for me by now, but in general) — David Carlisle, Mar 08 '18 at 23:21

score 7 · Accepted Answer · edited Feb 07 '22 at 16:28

7

\documentclass{article}
\newcounter{zzz}
\makeatletter
\def\aboveorbelow#1{%
\stepcounter{zzz}%
\edef\zztmp{\xdef\string\zzz\Roman{zzz}}%
\write@auxout\expandafter{\zztmp{\string@ifundefined{r@#1}{below}{above}}}%
\csname zzz\Roman{zzz}\endcsname}
\makeatother
\begin{document}
\section{Animals}
\label{sec:animals}
% etc. etc.
\section{Another section}
The quick brown fox (from \ref{sec:animals} \aboveorbelow{sec:animals})
jumped over the lazy dog.
The quick brown fox (from \ref{sec:plants} \aboveorbelow{sec:plants})
jumped over the lazy dog.
\section{Plants}
\label{sec:plants}
\end{document}

edited Feb 07 '22 at 16:28

gusbrs

13,740

answered Mar 08 '18 at 20:21

David Carlisle

757,742

So, I understand putting an "if undefined" in the aux file. But - why do we need to use a counter for this? – einpoklum Mar 08 '18 at 21:41
@einpoklum look in the aux file you need to make a unique command defined to above or below for each use, the counter just arranges that. – David Carlisle Mar 08 '18 at 22:39
@DavidCarlisle I took the liberty of adding an eol % before egreg spotted it, I hope it's ok. Pretty cool answer, thanks! – gusbrs Feb 07 '22 at 16:29
@gusbrs cruel, removing egreg's one pleasure in life. – David Carlisle Feb 07 '22 at 16:34

Let's get it just right: An \aboveorbelow{some-label} command

1 Answers1