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From: dhosek@sif.claremont.edu (Hosek, Donald A.)
Newsgroups: comp.text.tex
Subject: Re: listoffigures question/problem
Summary: \underline causes a jump out of mathmode for some reason
Keywords: latex listoffigures math mode
Message-ID: <7914@jarthur.Claremont.EDU>
Date: 24 Jul 90 17:18:23 GMT
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In article <26AB19EC.17589@maccs.dcss.mcmaster.ca>, art@maccs.dcss.mcmaster.ca (Art Mulder) writes...

>Hello all,
>  I trying to get \listoffigures to work and am having some difficulty.

>I have some simple macro's:
>|  \newcommand{\un}{\underline}
>|  \newcommand{\pth}[1]{\un{path} \; #1 \; \un{end}}

>used in a caption of a figure as follows:
>|  \caption{Labelled sm net intuitively corresponding to $\pth{a;a}$
>|           \label{fig:227}}

>which puts the following into my .lof file:
>[originally this was all one line, I have inserted line breaks]
>|  \contentsline {figure}{\numberline {2.30}{\ignorespaces Labelled
>|  sm net intuitively corresponding to $\relax $\@@underline {\hbox
>|  {path}}$\relax \mskip \thickmuskip a;a \mskip \thickmuskip \relax
>|  $\@@underline {\hbox {end}}$\relax $ }}{81}

p. 51 of the LaTeX book:

  The \underline command is fragile

Hmm... let's look up fragile in the index. pp. 151-2:

  Certain command arguments are called moving arguments. A
  fragile command that appears in a moving argument must be
  preceded by a \protect command... The following are all the
  commands and environments with moving arguments:

  o Commands with an argument that may be put into a table of
    contents, list of figures, or list of tables:
    \addcontentslne, \addtocontents, \caption, and the sectioning
    commands.

Hmm, that means \underline is fragile, \caption has a moving
argument, and we need to put \protect before \underline.

Changing the definition of \un to:

\newcommand{\un}{\protect\underline}

will do the trick.

Homework: What happens if \protect is used outside of a moving
argument? Cite the LaTeX manual to back up your assertion.

-dh

---
Don Hosek                         TeX, LaTeX, and Metafont Consulting and
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