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diff --git a/Master/texmf-dist/doc/generic/FAQ-en/html/FAQ-extrabrace.html b/Master/texmf-dist/doc/generic/FAQ-en/html/FAQ-extrabrace.html new file mode 100644 index 00000000000..1f68cf4bd74 --- /dev/null +++ b/Master/texmf-dist/doc/generic/FAQ-en/html/FAQ-extrabrace.html @@ -0,0 +1,65 @@ +<head> +<title>UK TeX FAQ -- question label extrabrace</title> +</head><body> +<h3>An extra ‘<code>}</code>’??</h3> +<!-- caption heading --> +<p/>You’ve looked at your LaTeX source and there’s no sign of a misplaced +<code>}</code> on the line in question. +<p/>Well, no: this is TeX’s cryptic way of hinting that you’ve put a +<a href="FAQ-protect.html">fragile command</a> in a moving argument. + +<p/>For example, <code>\</code><code>footnote</code> is fragile, and if we put that in the +moving argument of a <code>\</code><code>section</code> command, as +<blockquote> + +<pre> +\section{Mumble\footnote{I couldn't think of anything better}} +</pre> +</blockquote><p> +we get told +<blockquote> +<pre> +! Argument of \@sect has an extra }. +</pre> +</blockquote><p> +The same happens with captions (the following is a simplification of a +<i>comp.text.tex</i> post): +<blockquote> +<pre> +\caption{Energy: \[e=mc^2\]} +</pre> +</blockquote><p> +giving us the error message +<blockquote> +<pre> +! Argument of \@caption has an extra }. +</pre> +</blockquote><p> +The solution is usually to use a robust command in place of the one +you are using, or to force your command to be robust by prefixing it +with <code>\</code><code>protect</code>, which in the <code>\</code><code>section</code> case would show as +<blockquote> + +<pre> +\section{Mumble\protect\footnote{I couldn't think of anything better}} +</pre> +</blockquote><p> +In both the <code>\</code><code>section</code> case and the <code>\</code><code>caption</code> case, you can +separate the moving argument, as in +<code>\</code><code>section[</code><em>moving</em><code>]{</code><em>static</em><code>}</code>; this gives us another standard +route — simply to omit (or otherwise sanitise) the fragile command +in the moving argument. So, one might rewrite the <code>\</code><code>caption</code> +example as: +<blockquote> + +<pre> +\caption[Energy: $E=mc^2$]{Energy: \[E=mc^2\]} +</pre> +</blockquote><p> +for, after all, even if you want display maths in a caption, you +surely don’t want it in the list of figures. +<p/>The case of footnotes is somewhat more complex; +“<a href="FAQ-ftnsect.html">footnotes in LaTeX section headings</a>” +deals specifically with that issue. +<p/><p>This question on the Web: <a href="http://www.tex.ac.uk/cgi-bin/texfaq2html?label=extrabrace">http://www.tex.ac.uk/cgi-bin/texfaq2html?label=extrabrace</a> +</body> |