/usr/share/doc/fweb/html-info/Macro-protection.html is in fweb-doc 1.62-13.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 | <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<!-- Created by GNU Texinfo 6.1, http://www.gnu.org/software/texinfo/ -->
<head>
<title>FWEB: Macro protection</title>
<meta name="description" content="FWEB: Macro protection">
<meta name="keywords" content="FWEB: Macro protection">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="makeinfo">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link href="index.html#Top" rel="start" title="Top">
<link href="Concept-index.html#Concept-index" rel="index" title="Concept index">
<link href="Parameter-index.html#SEC_Contents" rel="contents" title="Table of Contents">
<link href="Macro-features.html#Macro-features" rel="up" title="Macro features">
<link href="Tokens.html#Tokens" rel="next" title="Tokens">
<link href="Recursion.html#Recursion" rel="prev" title="Recursion">
<style type="text/css">
<!--
a.summary-letter {text-decoration: none}
blockquote.indentedblock {margin-right: 0em}
blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
blockquote.smallquotation {font-size: smaller}
div.display {margin-left: 3.2em}
div.example {margin-left: 3.2em}
div.lisp {margin-left: 3.2em}
div.smalldisplay {margin-left: 3.2em}
div.smallexample {margin-left: 3.2em}
div.smalllisp {margin-left: 3.2em}
kbd {font-style: oblique}
pre.display {font-family: inherit}
pre.format {font-family: inherit}
pre.menu-comment {font-family: serif}
pre.menu-preformatted {font-family: serif}
pre.smalldisplay {font-family: inherit; font-size: smaller}
pre.smallexample {font-size: smaller}
pre.smallformat {font-family: inherit; font-size: smaller}
pre.smalllisp {font-size: smaller}
span.nolinebreak {white-space: nowrap}
span.roman {font-family: initial; font-weight: normal}
span.sansserif {font-family: sans-serif; font-weight: normal}
ul.no-bullet {list-style: none}
-->
</style>
</head>
<body lang="en">
<a name="Macro-protection"></a>
<div class="header">
<p>
Previous: <a href="Recursion.html#Recursion" accesskey="p" rel="prev">Recursion</a>, Up: <a href="Macro-features.html#Macro-features" accesskey="u" rel="up">Macro features</a> [<a href="Parameter-index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-index.html#Concept-index" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<a name="Protecting-macros-against-redefinition"></a>
<h4 class="subsubsection">7.2.1.3 Protecting macros against redefinition</h4>
<a name="index-Macros_002c-redefinition-of"></a>
<p>Normally an <small>FWEB</small> macro can be redefined at will. The example
</p>
<div class="example">
<pre class="example">@m PI 3.14159
@m PI (-3)
</pre></div>
<p>is permissible, but probably not a good idea. If you want to ensure
that a crucial macro definition is never redefined inadvertently, say
‘<samp>@m!</samp>’, as in
</p>
<div class="example">
<pre class="example">@m! PI 3.14159
</pre></div>
<p>That is called <em>protecting</em> the macro.
</p>
<p><small>FWEB</small>’s built-in functions and macros (beginning with ‘<samp>$</samp>’) are
protected by default; see
<a href="Protection.html#Protection">Protection</a>. To override that protection, use the command-line
options ‘<samp>-Tb</samp>’ (<a href="_002dTb.html#g_t_002dTb">-Tb</a>; for built-in functions) or ‘<samp>-Tm</samp>’
(<a href="_002dTm.html#g_t_002dTm">-Tm</a>; for macros).
</p>
</body>
</html>
|