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<title>for - m4 FOR Macro</title>
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<h1 align="center">for - m4 FOR Macro</h1>
<h2>Introduction</h2>
<p>detail/for.m4 provides <span class="code">BOOST_M4_FOR</span>, an
<strong>m4</strong> macro that provides the equivalent of a <span class=
"code">#for</span> preprocessor instruction.</p>
<h2>Usage</h2>
<p>This macro must be used by an <strong>m4</strong> file. This file
assumes that the option <span class="code">-P</span> is used, to force an
<span class="code">m4_</span> prefix on all builtin symbols.</p>
<h2>Arguments</h2>
<ol>
<li>The name of a variable to hold the current value.</li>
<li>The starting value of the variable.</li>
<li>The ending value of the variable.</li>
<li>The text to repeat. This text may contain references to the variable,
which will be replaced with the variable's current value.</li>
<li>The delimeter text (optional).</li>
</ol>
<p>If called with the wrong number of arguments (less than 4 or more than
5), <span class="code">BOOST_M4_FOR</span> will exit with an error. If the
starting value (<span class="code">$2</span>) is greater than or equal to
the ending value (<span class="code">$3</span>), <span class=
"code">BOOST_M4_FOR</span> will do nothing. Otherwise, it will repeat the
text (<span class="code">$4</span>), binding the variable (<span class=
"code">$1</span>) to the values in the range [starting value (<span class=
"code">$2</span>), ending value (<span class="code">$3</span>)), and repeat
the delimeter text (<span class="code">$5</span>) in-between each
occurrence of the repeat text (<span class="code">$4</span>).</p>
<h2>Examples</h2>
<p>Note of the quotation marks (<span class="m4">"</span>) used in the
table below are in the input or output; they are shown to delimit
whitespace. All code within a pair of quotation marks is intended to be on
one line.</p>
<table border align="center" summary="">
<tr>
<th>Input</th>
<th>Output</th>
</tr>
<tr>
<td class="m4">"BOOST_M4_FOR(i, 1, 3)"</td>
<td>Boost m4 script: BOOST_M4_FOR: Wrong number of arguments (3)</td>
</tr>
<tr>
<td class="m4">"BOOST_M4_FOR(i, 1, 3, i, ` ', 13)"</td>
<td>Boost m4 script: BOOST_M4_FOR: Wrong number of arguments (6)</td>
</tr>
<tr>
<td class="m4">"BOOST_M4_FOR(i, 7, 0, i )"</td>
<td>(nothing)</td>
</tr>
<tr>
<td class="m4">"BOOST_M4_FOR(i, 0, 0, i )"</td>
<td>(nothing)</td>
</tr>
<tr>
<td class="m4">"BOOST_M4_FOR(i, 0, 7, i )"</td>
<td class="m4">"0 1 2 3 4 5 6 "</td>
</tr>
<tr>
<td class="m4">"BOOST_M4_FOR(i, -13, -10, i )"</td>
<td class="m4">"-13 -12 -11 "</td>
</tr>
<tr>
<td class="m4">"BOOST_M4_FOR(i, 0, 8, BOOST_M4_FOR(j, 0, 4, (i, j)
)"<br>
")"</td>
<td class="m4">"(0, 0) (0, 1) (0, 2) (0, 3) "<br>
"(1, 0) (1, 1) (1, 2) (1, 3) "<br>
"(2, 0) (2, 1) (2, 2) (2, 3) "<br>
"(3, 0) (3, 1) (3, 2) (3, 3) "<br>
"(4, 0) (4, 1) (4, 2) (4, 3) "<br>
"(5, 0) (5, 1) (5, 2) (5, 3) "<br>
"(6, 0) (6, 1) (6, 2) (6, 3) "<br>
"(7, 0) (7, 1) (7, 2) (7, 3) "<br>
""</td>
</tr>
<tr>
<td class="m4">"BOOST_M4_FOR(i, 7, 0, i, |)"</td>
<td>(nothing)</td>
</tr>
<tr>
<td class="m4">"BOOST_M4_FOR(i, 0, 0, i, |)"</td>
<td>(nothing)</td>
</tr>
<tr>
<td class="m4">"BOOST_M4_FOR(i, 0, 7, i, |)"</td>
<td class="m4">"0|1|2|3|4|5|6"</td>
</tr>
<tr>
<td class="m4">"BOOST_M4_FOR(i, -13, -10, i, `, ')"</td>
<td class="m4">"-13, -12, -11"</td>
</tr>
<tr>
<td class="m4">"BOOST_M4_FOR(i, 0, 8, `[BOOST_M4_FOR(j, 0, 4, (i, j),
`, ')]', `,"<br>
"')"</td>
<td class="m4">"[(0, 0), (0, 1), (0, 2), (0, 3)],"<br>
"[(1, 0), (1, 1), (1, 2), (1, 3)],"<br>
"[(2, 0), (2, 1), (2, 2), (2, 3)],"<br>
"[(3, 0), (3, 1), (3, 2), (3, 3)],"<br>
"[(4, 0), (4, 1), (4, 2), (4, 3)],"<br>
"[(5, 0), (5, 1), (5, 2), (5, 3)],"<br>
"[(6, 0), (6, 1), (6, 2), (6, 3)],"<br>
"[(7, 0), (7, 1), (7, 2), (7, 3)]"</td>
</tr>
</table>
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<p>Revised
<!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B, %Y" startspan -->05
December, 2006<!--webbot bot="Timestamp" endspan i-checksum="38516" --></p>
<p><i>Copyright © 2000, 2001 Stephen Cleary (scleary AT jerviswebb DOT
com)</i></p>
<p><i>Distributed under the Boost Software License, Version 1.0. (See
accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a>
or copy at <a href=
"http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</a>)</i></p>
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