<html> <head> <!-- Generated by the Spirit (http://spirit.sf.net) QuickDoc --> <title>Adding New Methods</title> <link rel="stylesheet" href="theme/style.css" type="text/css"> <link rel="prev" href="global_variables.html"> <link rel="next" href="inserting_code.html"> </head> <body> <table width="100%" height="48" border="0" cellspacing="2"> <tr> <td><img src="../../../../boost.png"> </td> <td width="85%"> <font size="6" face="Verdana, Arial, Helvetica, sans-serif"><b>Adding New Methods</b></font> </td> </tr> </table> <br> <table border="0"> <tr> <td width="30"><a href="../index.html"><img src="theme/u_arr.gif" border="0"></a></td> <td width="30"><a href="global_variables.html"><img src="theme/l_arr.gif" border="0"></a></td> <td width="20"><a href="inserting_code.html"><img src="theme/r_arr.gif" border="0"></a></td> </tr> </table> <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>-></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>& </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>"World"</span><span class=special>, </span><span class=string>"hello.h"</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>"greet"</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>>>> </span><span class=identifier>import </span><span class=identifier>hello </span><span class=special>>>> </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>() >>> </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>) >>> </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>>>> </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> <table border="0"> <tr> <td width="30"><a href="../index.html"><img src="theme/u_arr.gif" border="0"></a></td> <td width="30"><a href="global_variables.html"><img src="theme/l_arr.gif" border="0"></a></td> <td width="20"><a href="inserting_code.html"><img src="theme/r_arr.gif" border="0"></a></td> </tr> </table> <br> <hr size="1"><p class="copyright">Copyright © 2003 Bruno da Silva de Oliveira<br>Copyright © 2002-2003 Joel de Guzman<br><br> <font size="2">Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) </font> </p> </body> </html>