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diff --git a/Master/texmf-doc/doc/english/FAQ-en/html/FAQ-protect.html b/Master/texmf-doc/doc/english/FAQ-en/html/FAQ-protect.html deleted file mode 100644 index dd0389f9118..00000000000 --- a/Master/texmf-doc/doc/english/FAQ-en/html/FAQ-protect.html +++ /dev/null @@ -1,85 +0,0 @@ -<head> -<title>UK TeX FAQ -- question label protect</title> -</head><body> -<h3>What’s the reason for ‘protection’?</h3> -<p/>Sometimes LaTeX saves data it will reread later. These data are -often the argument of some command; they are the so-called moving -arguments. (‘Moving’ because data are moved around.) Candidates -are all arguments that may go into table of contents, list of figures, -<em>etc</em>.; namely, data that are written to an auxiliary file and -read in later. Other places are those data that might appear in head- -or footlines. Section headings and figure captions are the most -prominent examples; there’s a complete list in Lamport’s book -(see <a href="FAQ-books.html">TeX-related books</a>). -<p/>What’s going on really, behind the scenes? The commands in moving -arguments are normally expanded to their internal structure during the -process of saving. Sometimes this expansion results in invalid TeX -code, which shows either during expansion or when the code is -processed again. Protecting a command, using -“<code>\</code><code>protect</code><code>\</code><code>cmd</code>” tells LaTeX to save <code>\</code><code>cmd</code> as -<code>\</code><code>cmd</code>, without expanding it at all. -<p/>So, what is a ‘fragile command’? — it’s a command that expands into -illegal TeX code during the save process. -<p/>What is a ‘robust command’? — it’s a command that expands into legal -TeX code during the save process. -<p/>Lamport’s book says in its description of every LaTeX command whether -it is ‘robust’ or ‘fragile’; it also says that every command with an -optional argument is fragile. The list isn’t reliable, and neither -is the assertion about optional arguments; the statements may have -been true in early versions of LaTeX2e but are not any longer -necessarily so: -<ul> -<li> Some fragile commands, such as <code>\</code><code>cite</code>, have been made robust - in later revisions of LaTeX. -<li> Some commands, such as <code>\</code><code>end</code> and <code>\</code><code>nocite</code>, are fragile - even though they have no optional arguments. -<li> The “user’s way” of creating a command with an optional - argument (using <code>\</code><code>newcommand</code> or <code>\</code><code>newcommand*</code>) now always - creates a robust command (though macros without optional arguments - may still be fragile if they do things that are themselves fragile). -<li> There is no reason that a package author should not also make - robust commands with optional arguments as part of the package. -<li> Some robust commands are redefined by certain packages to be - fragile (the <code>\</code><code>cite</code> command commonly suffers this treatment). -</ul> -Further, simply “hiding” a fragile command in another command, has -no effect on fragility. So, if <code>\</code><code>fred</code> is fragile, and you write: -<blockquote> -<pre> -\newcommand{\jim}{\fred} -</pre> -</blockquote><p> -then <code>\</code><code>jim</code> is fragile too. There is, however, the -<code>\</code><code>newcommand</code>-replacement <code>\</code><code>DeclareRobustCommand</code>, which -<em>always</em> creates a robust command (whether or not it has optional -arguments). The syntax of <code>\</code><code>DeclareRobustCommand</code> is substantially -identical to that of <code>\</code><code>newcommand</code>, and if you do the wrapping -trick above as: -<blockquote> -<pre> -\DeclareRobustCommand{\jim}{\fred} -</pre> -</blockquote><p> -then <code>\</code><code>jim</code> is robust. -<p/>Finally, we have the <i>makerobust</i> package, which defines -<code>\</code><code>MakeRobustCommand</code> to convert a command to be robust. With the -package, the “wrapping” above can simply be replaced by: -<blockquote> -<pre> -\MakeRobustCommand\fred -</pre> -</blockquote><p> -Whereafter, <code>\</code><code>fred</code> is robust. Using the package may be reasonable -if you have lots of fragile commands that you need to use in moving -arguments. -<p/>In short, the situation is confusing. No-one believes this is -satisfactory; the LaTeX team have removed the need for -protection of some things, but the techniques available in -current LaTeX mean that this is an expensive exercise. It remains -a long-term aim of the team to remove all need for <code>\</code><code>protect</code>ion. -<dl> -<dt><tt><i>makerobust.sty</i></tt><dd>Distributed with Heiko Oberdiek’s packages - <a href="ftp://cam.ctan.org/tex-archive/macros/latex/contrib/oberdiek.zip">macros/latex/contrib/oberdiek</a> (<a href="ftp://cam.ctan.org/tex-archive/macros/latex/contrib/oberdiek.tar.gz">gzipped tar</a>, <a href="http://www.tex.ac.uk/tex-archive/macros/latex/contrib/oberdiek/">browse</a>) -</dl> -<p/><p>This question on the Web: <a href="http://www.tex.ac.uk/cgi-bin/texfaq2html?label=protect">http://www.tex.ac.uk/cgi-bin/texfaq2html?label=protect</a> -</body> |