Displaying plus and minus of a length

Question

I know that \the\somelength will show me the value of \somelength. But how do I find out what the current stretch on that length is?

For instance, if I have

\setlength{\footnotesep}{10 pt plus 5pt minus 3pt}

and I later want to display what the plus and the minus are for debugging purposes, how do I do that?

First response was to use \showthe. I tried that, but it doesn't give the plus and minus. Minimal example:

\documentclass{report}
\begin{document}
\scrollmode
\typeout{The footnotesep is \the\footnotesep,}
\showthe\footnotesep
\setlength{\footnotesep}{10 pt plus 5pt minus 3pt}
\typeout{The footnotesep is now \the\footnotesep,}
\showthe\footnotesep
\end{document}

Output on the console:

`The footnotesep is 6.65pt,
 > 6.65pt.
 l.6 \showthe\footnotesep

 The footnotesep is now 10.0pt,
 > 10.0pt.
 l.9 \showthe\footnotesep

`

But I want to see the plus and minus values.

\showthe\footnotesep (but the\footnotesep will give the same information in the document as opposed to the log) — David Carlisle, Jul 15 '14 at 15:53
Neither \showthe nor \the seems to be outputting the 'plus' or 'minus'. [And now I don't seem to be able to use any markup, or even insert a newline--the moment I hit , I get a posting. Maybe I need to edit my original post?] — Mike Maxwell, Jul 15 '14 at 16:20
@egreg: Ok...that was not what I was expecting! I think I need to ask a new question, because I'm sometimes getting extra vertical space between two footnotes. I assumed that was because of rubber, but I guess that can't be the explanation. (I also wonder why I'm not getting a warning when I try to do \setlength to \footnotesep, and include a plus and minus...) — Mike Maxwell, Jul 15 '14 at 16:37
Re my final post, the extra space between the footnotes turns out to be a minor bug in particular package. My hypothesis that it was caused by \footnotesep was wrong. — Mike Maxwell, Jul 15 '14 at 21:57

score 2 · Accepted Answer · answered Jul 15 '14 at 16:34

You can't display the plus or minus components of \footnotesep because it can't have them, being defined by

\newdimen\footnotesep

which makes it a rigid length parameter.

If you do

\setlength{\footnotesep}{10pt plus 5pt minus 3pt}

LaTeX will set \footnotesep to 10pt (and this explains the result of \showthe\footnotesep) and typesets plus 5pt minus 3pt). If you do the setting in the preamble you'll receive a No \begin{document} error.

score 2 · Answer 2 · answered Jul 15 '14 at 16:42

You are probably thinking of the following construction (\Footnotesep in the example). Because the name is not reserved to the other construction (\dimen), the result is as expected.

\documentclass{report}
\begin{document}
\scrollmode
\typeout{The footnotesep is \the\footnotesep,}
\showthe\footnotesep

\the\footnotesep
%\setlength{\footnotesep}{10 pt plus 5pt minus 3pt}
\newlength\Footnotesep
\setlength{\Footnotesep}{10pt plus 5pt minus 3pt}
\typeout{The footnotesep is now \the\Footnotesep,}

B
\showthe\Footnotesep

\the\Footnotesep

\end{document}

Displaying plus and minus of a length

2 Answers2