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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>-></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> |
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| <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> |
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