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 29<div class="toc"><dl>
 30<dt><span class="section"><a href="statement/block_statement.html">Block Statement</a></span></dt>
 31<dt><span class="section"><a href="statement/if__statement.html">if_ Statement</a></span></dt>
 32<dt><span class="section"><a href="statement/___if_else_____statement.html">if_else_ Statement</a></span></dt>
 33<dt><span class="section"><a href="statement/switch__statement.html">switch_
 34        Statement</a></span></dt>
 35<dt><span class="section"><a href="statement/while__statement.html">while_
 36        Statement</a></span></dt>
 37<dt><span class="section"><a href="statement/___do_while_____statement.html">do_while_ Statement</a></span></dt>
 38<dt><span class="section"><a href="statement/for_statement.html">for_ Statement</a></span></dt>
 39<dt><span class="section"><a href="statement/try__catch__statement.html">try_
 40        catch_ Statement</a></span></dt>
 41<dt><span class="section"><a href="statement/throw_.html">throw_</a></span></dt>
 42</dl></div>
 43<p>
 44        <span class="bold"><strong><span class="emphasis"><em>Lazy statements...</em></span></strong></span>
 45      </p>
 46<p>
 47        The expressions presented so far are sufficiently powerful to construct quite
 48        elaborate structures. We have presented lazy-functions and lazy-operators.
 49        How about lazy-statements? First, an appetizer:
 50      </p>
 51<p>
 52        Print all odd-numbered contents of an STL container using <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">for_each</span></code>
 53        (<a href="../../../../example/all_odds.cpp" target="_top">all_odds.cpp</a>):
 54      </p>
 55<pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">for_each</span><span class="special">(</span><span class="identifier">c</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">c</span><span class="special">.</span><span class="identifier">end</span><span class="special">(),</span>
 56    <span class="identifier">if_</span><span class="special">(</span><span class="identifier">arg1</span> <span class="special">%</span> <span class="number">2</span> <span class="special">==</span> <span class="number">1</span><span class="special">)</span>
 57    <span class="special">[</span>
 58        <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">arg1</span> <span class="special">&lt;&lt;</span> <span class="char">' '</span>
 59    <span class="special">]</span>
 60<span class="special">);</span>
 61</pre>
 62<p>
 63        Huh? Is that valid C++? Read on...
 64      </p>
 65<p>
 66        Yes, it is valid C++. The sample code above is as close as you can get to
 67        the syntax of C++. This stylized C++ syntax differs from actual C++ code.
 68        First, the <code class="computeroutput"><span class="keyword">if</span></code> has a trailing
 69        underscore. Second, the block uses square brackets instead of the familiar
 70        curly braces {}.
 71      </p>
 72<div class="note"><table border="0" summary="Note">
 73<tr>
 74<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../../doc/src/images/note.png"></td>
 75<th align="left">Note</th>
 76</tr>
 77<tr><td align="left" valign="top">
 78<p>
 79          <span class="bold"><strong>C++ in C++?</strong></span>
 80        </p>
 81<p>
 82          In as much as <a href="http://spirit.sourceforge.net" target="_top">Spirit</a>
 83          attempts to mimic EBNF in C++, Phoenix attempts to mimic C++ in C++!!!
 84        </p>
 85</td></tr>
 86</table></div>
 87<div class="note"><table border="0" summary="Note">
 88<tr>
 89<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../../doc/src/images/note.png"></td>
 90<th align="left">Note</th>
 91</tr>
 92<tr><td align="left" valign="top"><p>
 93          Unlike lazy functions and lazy operators, lazy statements always return
 94          void.
 95        </p></td></tr>
 96</table></div>
 97<p>
 98        Here are more examples with annotations. The code almost speaks for itself.
 99      </p>
100</div>
101<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
102<td align="left"></td>
103<td align="right"><div class="copyright-footer">Copyright &#169; 2002-2005, 2010 Joel de Guzman, Dan Marsden, Thomas Heller<p>
104        Distributed under the Boost Software License, Version 1.0. (See accompanying
105        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
106      </p>
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