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diff --git a/Master/texmf-dist/doc/generic/FAQ-en/html/FAQ-labundef.html b/Master/texmf-dist/doc/generic/FAQ-en/html/FAQ-labundef.html deleted file mode 100644 index 03445bd2ff7..00000000000 --- a/Master/texmf-dist/doc/generic/FAQ-en/html/FAQ-labundef.html +++ /dev/null @@ -1,39 +0,0 @@ -<head> -<title>UK TeX FAQ -- question label labundef</title> -</head><body> -<h3>Finding if a label is undefined</h3> -<p/>People seem to want to know (at run time) if a label is undefined (I -don’t actually understand <em>why</em>, particularly: it’s a transient -state, and LaTeX deals with it quite well). -<p/>A resolved label is simply a command: -<code>\</code><code>r@</code><code><<i>label-name</i>></code>; determining if the label is set is -then simply a matter of detecting if the command exists. The usual -LaTeX internal way of doing this is to use the command -<code>\</code><code>@ifundefined</code>: -<blockquote> - <code>\</code><code>@ifundefined{</code><em></em>r@<em>label-name</em><code>}{</code><em>undef-cmds</em><code>}{</code><em>def-cmds</em><code>}</code> -</blockquote><p> -In which, <<i>label-name</i>> is exactly what you would use in -a <code>\</code><code>label</code> command, and the remaining two arguments are command -sequences to be used if the label is undefined -(<<i>undef-cmds</i>>) or if it is defined -(<<i>def-cmds</i>>). -<p/>Note that any command that incorporates <code>\</code><code>@ifundefined</code> is naturally -fragile, so remember to create it with <code>\</code><code>DeclareRobustCommand</code> or to -use it with <code>\</code><code>protect</code> in a moving argument. -<p/>If you’re into this game, you may well not care about LaTeX’s -warning about undefined labels at the end of the document; however, -if you are, include the command <code>\</code><code>G@refundefinedtrue</code> in -<<i><code>undef-cmds</i>></code>. -<p/>And of course, remember you’re dealing in internal commands, and pay -attention to the <a href="FAQ-atsigns.html">at-signs</a>. -<p/>All the above can be avoided by using the <i>labelcas</i> package: -it provides commands that enable you to switch according to the state -of a single label, or the states of a list of labels. The package’s -definition is a bit complicated, but the package itself is pretty -powerful. -<dl> -<dt><tt><i>labelcas.sty</i></tt><dd><a href="http://mirror.ctan.org/macros/latex/contrib/labelcas.zip">macros/latex/contrib/labelcas</a> (or <a href="http://mirror.ctan.org/macros/latex/contrib/labelcas/">browse the directory</a>); <a href="http://mirror.ctan.org/help/Catalogue/entries/labelcas.html">catalogue entry</a> -</dl> -<p/><p>This question on the Web: <a href="http://www.tex.ac.uk/cgi-bin/texfaq2html?label=labundef">http://www.tex.ac.uk/cgi-bin/texfaq2html?label=labundef</a> -</body> |