<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <!-- Copyright David Abrahams 2006. 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) --> <html> <head> <meta name="generator" content= "HTML Tidy for Cygwin (vers 1st April 2002), see www.w3.org"> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <link rel="stylesheet" type="text/css" href="../boost.css"> <title>Boost.Python - <boost/python/args.hpp></title> </head> <body> <table border="0" cellpadding="7" cellspacing="0" width="100%" summary= "header"> <tr> <td valign="top" width="300"> <h3><a href="../../../../index.htm"><img height="86" width="277" alt="C++ Boost" src="../../../../boost.png" border="0"></a></h3> </td> <td valign="top"> <h1 align="center"><a href="../index.html">Boost.Python</a></h1> <h2 align="center">Header <boost/python/args.hpp></h2> </td> </tr> </table> <hr> <h2>Contents</h2> <dl class="page-index"> <dt><a href="#introduction">Introduction</a></dt> <dt><a href="#keyword-expression"><i>keyword-expressions</i></a></dt> <dt><a href="#classes">Classes</a></dt> <dd> <dl class="page-index"> <dt><a href="#arg-spec">class <code>arg</code></a></dt> <dd> <dl class="page-index"> <dt><a href="#arg-synopsis">class <code>arg</code> synopsis</a></dt> <dt><a href="#arg-ctor">class <code>arg</code> constructor</a></dt> <dt><a href="#arg-operator">class <code>arg</code> template <code>operator =</code></a></dt> </dl> </dd> </dl> </dd> <dt><a href="#keyword-expression-operators"><i>Keyword-expression</i> operator <code>,</code></a></dt> <dt><a href="#functions">Functions (deprecated)</a></dt> <dd> <dl class="page-index"> <dt><code><a href= "#args-spec">args</a>(</code>...<code>)</code></dt> </dl> </dd> <dt><a href="#examples">Example(s)</a></dt> </dl> <hr> <h2><a name="introduction"></a>Introduction</h2> <p>Supplies a family of overloaded functions for specifying argument keywords for wrapped C++ functions.</p> <h2><a name="keyword-expression"></a><i>keyword-expressions</i></h2> <p>A <b>keyword-expression</b> results in an object which holds a sequence of <a href="definitions.html#ntbs">ntbs</a>es, and whose type encodes the number of keywords specified. The <b>keyword-expression</b> may contain default values for some or all of the keywords it holds</p> <h2><a name="classes"></a>Classes</h2> <h3><a name="arg-spec"></a><code>class arg;</code></h3> <p>The objects of class arg are keyword-expressions holding one keyword ( size one )</p> <h4><a name="arg-synopsis"></a>Class <code>arg</code> synopsis</h4> <pre> namespace boost { namespace python { struct arg { template <class T> arg &perator = (T const &value); explicit arg (char const *name){elements[0].name = name;} }; }} </pre> <h4><a name="arg-ctor"></a>Class <code>arg</code> constructor</h4> <pre> arg(char const* name); </pre> <dl class="function-semantics"> <dt><b>Requires:</b> The argument must be a <a href= "definitions.html#ntbs">ntbs</a>.</dt> <dt><b>Effects:</b> Constructs an <code>arg</code> object holding a keyword with name <code>name</code>.</dt> </dl> <h4><a name="arg-operator"></a>Class <code>arg</code> operator =</h4> <pre> template <class T> arg &operator = (T const &value); </pre> <dl class="function-semantics"> <dt><b>Requires:</b> The argument must convertible to python.</dt> <dt><b>Effects:</b> Assigns default value for the keyword.</dt> <dt><b>Returns:</b> Reference to <code>this</code>.</dt> </dl> <h2><a name="keyword-expression-operators"><i>Keyword-expression</i> operator <code>,</code></a></h2> <pre> <i>keyword-expression</i> operator , (<i>keyword-expression</i>, const arg &kw) const <i>keyword-expression</i> operator , (<i>keyword-expression</i>, const char *name) const; </pre> <dl class="function-semantics"> <dt><b>Requires:</b> The argument <code>name</code> must be a <a href= "definitions.html#ntbs">ntbs</a>.</dt> <dt><b>Effects:</b> Extends the <i>keyword-expression</i> argument with one more keyword.</dt> <dt><b>Returns:</b> The extended <i>keyword-expression</i>.</dt> </dl> <h2><font color="#7F7F7F"><a name="functions"></a>Functions (deprecated)</font></h2> <h3><a name="args-spec"></a><code><font color= "#7F7F7F">args</font>(</code>...<code>)</code></h3> <pre> <font color="#7F7F7F"> <i>unspecified1</i> args(char const*); <i>unspecified2</i> args(char const*, char const*); . . . <i>unspecifiedN</i> args(char const*, char const*, ... char const*); </font> </pre> <dl class="function-semantics"> <dt><font color="#7F7F7F"><b>Requires:</b> Every argument must be a <a href="definitions.html#ntbs">ntbs</a>.</font></dt> <dt><font color="#7F7F7F"><b>Returns:</b> an object representing a <a href="#keyword-expression"><i>keyword-expression</i></a> encapsulating the arguments passed.</font></dt> </dl> <h2><a name="examples"></a>Example</h2> <pre> #include <boost/python/def.hpp> using namespace boost::python; int f(double x, double y, double z=0.0, double w=1.0); BOOST_PYTHON_MODULE(xxx) { def("f", f , ( arg("x"), "y", arg("z")=0.0, arg("w")=1.0 ) ); } </pre> <p>Revised 01 August, 2003</p> <p><i>© Copyright <a href= "http://www.boost.org/people/dave_abrahams.htm">Dave Abrahams</a> 2002-2003.</i></p> </body> </html>