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<title>Adding New Methods</title>
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      <font size="6" face="Verdana, Arial, Helvetica, sans-serif"><b>Adding New Methods</b></font>
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<p>
Suppose that you want to add a function to a class, turning it into a member
function:</p>
<code><pre>
    <span class=keyword>struct </span><span class=identifier>World
    </span><span class=special>{
        </span><span class=keyword>void </span><span class=identifier>set</span><span class=special>(</span><span class=identifier>std</span><span class=special>::</span><span class=identifier>string </span><span class=identifier>msg</span><span class=special>) { </span><span class=keyword>this</span><span class=special>-&gt;</span><span class=identifier>msg </span><span class=special>= </span><span class=identifier>msg</span><span class=special>; }
        </span><span class=identifier>std</span><span class=special>::</span><span class=identifier>string </span><span class=identifier>msg</span><span class=special>;
    };

    </span><span class=identifier>std</span><span class=special>::</span><span class=identifier>string </span><span class=identifier>greet</span><span class=special>(</span><span class=identifier>World</span><span class=special>&amp; </span><span class=identifier>w</span><span class=special>)
    {
        </span><span class=keyword>return </span><span class=identifier>w</span><span class=special>.</span><span class=identifier>msg</span><span class=special>;
    }
</span></pre></code>
<p>
Here, we want to make <tt>greet</tt> work as a member function of the class <tt>World</tt>. We do
that using the <tt>add_method</tt> construct:</p>
<code><pre>
    <span class=identifier>W </span><span class=special>= </span><span class=identifier>Class</span><span class=special>(</span><span class=string>&quot;World&quot;</span><span class=special>, </span><span class=string>&quot;hello.h&quot;</span><span class=special>)
    </span><span class=identifier>add_method</span><span class=special>(</span><span class=identifier>W</span><span class=special>, </span><span class=string>&quot;greet&quot;</span><span class=special>)
</span></pre></code>
<p>
Notice also that then you can rename it, set its policy, just like a regular
member function:</p>
<code><pre>
    <span class=identifier>rename</span><span class=special>(</span><span class=identifier>W</span><span class=special>.</span><span class=identifier>greet</span><span class=special>, </span><span class=literal>'Greet'</span><span class=special>)
</span></pre></code>
<p>
Now from Python:</p>
<code><pre>
    <span class=special>&gt;&gt;&gt; </span><span class=identifier>import </span><span class=identifier>hello
    </span><span class=special>&gt;&gt;&gt; </span><span class=identifier>w </span><span class=special>= </span><span class=identifier>hello</span><span class=special>.</span><span class=identifier>World</span><span class=special>()
    &gt;&gt;&gt; </span><span class=identifier>w</span><span class=special>.</span><span class=identifier>set</span><span class=special>(</span><span class=literal>'Ni'</span><span class=special>)
    &gt;&gt;&gt; </span><span class=identifier>w</span><span class=special>.</span><span class=identifier>greet</span><span class=special>()
    </span><span class=literal>'Ni'
    </span><span class=special>&gt;&gt;&gt; </span><span class=identifier>print </span><span class=literal>'Oh no! The knights who say Ni!'
    </span><span class=identifier>Oh </span><span class=identifier>no</span><span class=special>! </span><span class=identifier>The </span><span class=identifier>knights </span><span class=identifier>who </span><span class=identifier>say </span><span class=identifier>Ni</span><span class=special>!
</span></pre></code>
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<hr size="1"><p class="copyright">Copyright &copy; 2003 Bruno da Silva de Oliveira<br>Copyright &copy; 2002-2003 Joel de Guzman<br><br>
<font size="2">Permission to copy, use, modify, sell and distribute this document
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