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tutorial update

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[SVN r17512]
This commit is contained in:
Joel de Guzman
2003-02-18 18:44:16 +00:00
parent 472dc3bd41
commit ff9f262fac
22 changed files with 561 additions and 221 deletions
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10
doc/tutorial/doc/extracting_c___objects.html
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@@ -28,7 +28,7 @@
At some point, we will need to get C++ values out of object instances. This
can be achieved with the <tt>extract&lt;T&gt;</tt> function. Consider the following:</p>
<code><pre>
<span class=keyword>double </span><span class=identifier>x </span><span class=special>= </span><span class=identifier>o</span><span class=special>.</span><span class=identifier>attr</span><span class=special>(</span><span class=string>&quot;length&quot;</span><span class=special>); </span><span class=comment>// compile error
<span class=keyword>double </span><span class=identifier>x </span><span class=special>= </span><span class=identifier>o</span><span class=special>.</span><span class=identifier>attr</span><span class=special>(</span><span class=string>&quot;length&quot;</span><span class=special>); // </span><span class=identifier>compile </span><span class=identifier>error
</span></pre></code>
<p>
In the code above, we got a compiler error because Boost.Python
@@ -52,15 +52,15 @@ appropriate exception is thrown. To avoid an exception, we need to
test for extractibility:</p>
<code><pre>
<span class=identifier>extract</span><span class=special>&lt;</span><span class=identifier>Vec2</span><span class=special>&amp;&gt; </span><span class=identifier>x</span><span class=special>(</span><span class=identifier>o</span><span class=special>);
</span><span class=keyword>if </span><span class=special>(</span><span class=identifier>x</span><span class=special>.</span><span class=identifier>check</span><span class=special>()) </span><span class=special>{
</span><span class=identifier>Vec2</span><span class=special>&amp; </span><span class=identifier>v </span><span class=special>= </span><span class=identifier>x</span><span class=special>(); </span><span class=special>...
</span><span class=keyword>if </span><span class=special>(</span><span class=identifier>x</span><span class=special>.</span><span class=identifier>check</span><span class=special>()) {
</span><span class=identifier>Vec2</span><span class=special>&amp; </span><span class=identifier>v </span><span class=special>= </span><span class=identifier>x</span><span class=special>(); ...
</span></pre></code>
<p>
<img src="theme/bulb.gif"></img> The astute reader might have noticed that the <tt>extract&lt;T&gt;</tt>
facility in fact solves the mutable copying problem:</p>
<code><pre>
<span class=identifier>dict </span><span class=identifier>d </span><span class=special>= </span><span class=identifier>extract</span><span class=special>&lt;</span><span class=identifier>dict</span><span class=special>&gt;(</span><span class=identifier>x</span><span class=special>.</span><span class=identifier>attr</span><span class=special>(</span><span class=string>&quot;__dict__&quot;</span><span class=special>));
</span><span class=identifier>d</span><span class=special>[</span><span class=literal>'whatever'</span><span class=special>] </span><span class=special>= </span><span class=number>3</span><span class=special>; </span>#<span class=identifier>modifies </span><span class=identifier>x</span><span class=special>.</span><span class=identifier>__dict__ </span><span class=special>!
</span><span class=identifier>d</span><span class=special>[</span><span class=literal>'whatever'</span><span class=special>] = </span><span class=number>3</span><span class=special>; </span>##<span class=identifier>modifies </span><span class=identifier>x</span><span class=special>.</span><span class=identifier>__dict__ </span><span class=special>!
</span></pre></code>
<table border="0">
<tr>
@@ -70,7 +70,7 @@ facility in fact solves the mutable copying problem:</p>
</tr>
</table>
<br>
<hr size="1"><p class="copyright">Copyright &copy; 2002 David Abrahams<br>Copyright &copy; 2002 Joel de Guzman<br><br>
<hr size="1"><p class="copyright">Copyright &copy; 2002-2003 David Abrahams<br>Copyright &copy; 2002-2003 Joel de Guzman<br><br>
<font size="2">Permission to copy, use, modify, sell and distribute this document
is granted provided this copyright notice appears in all copies. This document
is provided &quot;as is&quot; without express or implied warranty, and with