Master/texmf-doc/doc/english/FAQ-en/html/FAQ-compjobnam.html


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<head>
<title>UK TeX FAQ -- question label compjobnam</title>
</head><body>
<h3>Comparing the &ldquo;job name&rdquo;</h3>
<p/>The token <code>\</code><code>jobname</code> amusingly produces a sequence of characters
whose category code is 12 (&lsquo;other&rsquo;), regardless of what the characters
actually are.  Since one inevitably has to compare a macro with the
contents of another macro (using <code>\</code><code>ifx</code>, somewhere) one needs to
create a macro whose expansion looks the same as the expansion of
<code>\</code><code>jobname</code>.  We find we can do this with <code>\</code><code>meaning</code>, if we strip
the &ldquo;<code>\</code><code>show</code> command&rdquo; prefix.
<p/>The full command looks like:
<blockquote>
<pre>
\def\StripPrefix#1&gt;{}
\def\jobis#1{FF\fi
  \def\predicate{#1}%
  \edef\predicate{\expandafter\StripPrefix\meaning\predicate}%
  \edef\job{\jobname}%
  \ifx\job\predicate
}
</pre>

</blockquote><p>
And it&rsquo;s used as:
<blockquote>
<pre>
\if\jobis{mainfile}%
  \message{YES}%
\else
  \message{NO}%
\fi
</pre>
</blockquote><p>
Note that the command <code>\</code><code>StripPrefix</code> need not be defined if you&rsquo;re
using LaTeX &mdash; there&rsquo;s already an 
<a href="FAQ-atsigns.html">internal command</a> <code>\</code><code>strip@prefix</code> that you can
use.
<p/><p>This question on the Web: <a href="http://www.tex.ac.uk/cgi-bin/texfaq2html?label=compjobnam">http://www.tex.ac.uk/cgi-bin/texfaq2html?label=compjobnam</a>
</body>