boost-react-native-bundle

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">    <html> <head> <meta name="generator" content= "HTML Tidy for Windows (vers 1st August 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/overloads.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/overloads.hpp></h2> </td> </tr> </table> <hr> <h2>Contents</h2> <dl class="page-index"> <dt><a href="#introduction">Introduction</a></dt> <dt><a href= "#overload-dispatch-expression"><i>overload-dispatch-expressions</i></a></dt> <dt><a href= "#OverloadDispatcher-concept">OverloadDispatcher</a> concept</dt> <dt><a href="#macros">Macros</a></dt> <dd> <dl class="page-index"> <dt><a href= "#BOOST_PYTHON_FUNCTION_OVERLOADS-spec">BOOST_PYTHON_FUNCTION_OVERLOADS</a></dt> <dt><a href= "#BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS-spec">BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS</a></dt> </dl> </dd> <dt><a href="#examples">Example(s)</a></dt> </dl> <hr> <h2><a name="introduction"></a>Introduction</h2> <p>Defines facilities for generating families of overloaded Python functions and extension class methods from C++ functions and member functions with default arguments, or from similar families of C++ overloads</p> <h2><a name= "overload-dispatch-expression"></a><i>overload-dispatch-expressions</i></h2> <p> An <em>overload-dispatch-expression</em> is used to describe a family of overloaded methods to be generated for an extension class. It has the following properties: <blockquote> <dl class="properties"> <dt><b>docstring:</b> An <a href="definitions.html#ntbs">ntbs</a> whose value will bound to the methods' <code>__doc__</code> attribute</dt> <dt><b>keywords:</b> A <a href= "args.html#keyword-expression">keyword-expression</a> which will be used to name (a trailing subsequence of) the arguments to the generated methods.</dt> <dt><b>call policies:</b> An instance of some type which models <a href= "CallPolicies.html">CallPolicies</a>.</dt> <dt><b>minimum <a href="definitions.html#arity">arity</a></b> The minimum number of arguments to be accepted by a generated method overload.</dt> <dt><b>maximum <a href="definitions.html#arity">arity</a></b> The maximum number of arguments to be accepted by a generated method overload.</dt> </dl> </blockquote> <h2><a name="OverloadDispatcher-concept"></a>OverloadDispatcher Concept</h2> An OverloadDispatcher <code>X</code> is a class which has a <em>minimum arity</em> and a <em>maximum arity</em>, and for which the following following are valid <a href="#overload-dispatch-expression"><em>overload-dispatch-expression</em></a>s, with the same minimum and maximum arity as the OverloadDispatcher. <pre> X() X(docstring) X(docstring, keywords) X(keywords, docstring) X()[policies] X(docstring)[policies] X(docstring, keywords)[policies] X(keywords, docstring)[policies] </pre> <ul> <li>If <code>policies</code> are supplied, it must be an instance of a type which models <a href="CallPolicies.html#CallPolicies-concept">CallPolicies</a>, and will be used as the result's call policies. Otherwise the result's call policies will be an instance of <a href="default_call_policies.html#default_call_policies-spec">default_call_policies</a>. <li>If <code>docstring</code> is supplied it must be an <a href="definitions.html#ntbs">ntbs</a>, and will be used as the result's docstring. Otherwise the result has an empty docstring. <li>If <code>keywords</code> is supplied it must be the result of a <a href= "args.html#keyword-expression">keyword-expression</a> whose length is no greater than <code>X</code>'s maximum arity, and will be used as the result's keywords. Otherwise the result's keywords will be empty. </ul> <h2><a name="macros"></a>Macros</h2> <h3><a name= "BOOST_PYTHON_FUNCTION_OVERLOADS-spec">BOOST_PYTHON_FUNCTION_OVERLOADS(name, func_id, min_args, max_args)</a></h3> Expands to the definition of an OverloadDispatcher called <code>name</code> in the current scope which can be used to generate the following function invocation: <pre> func_id(a<small><i>1</i></small>, a<small><i>2</i></small>,...a<small><i>i</i></small>); </pre> for all <code>min_args</code> <= <i>i</i> <= <code>max_args</code>. <h3><a name= "BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS-spec">BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS(name, member_name, min_args, max_args)</a></h3> Expands to the definition of an OverloadDispatcher called <code>name</code> in the current scope which can be used to generate the following function invocation: <pre> x.member_name(a<small><i>1</i></small>, a<small><i>2</i></small>,...a<small><i>i</i></small>); </pre> for all <code>min_args</code> <= <i>i</i> <= <code>max_args</code>, where <code>x</code> is a reference to an object of class type. <h2><a name="examples"></a>Example(s)</h2> <pre> #include <boost/python/module.hpp> #include <boost/python/def.hpp> #include <boost/python/args.hpp> #include <boost/python/tuple.hpp> #include <boost/python/class.hpp> #include <boost/python/overloads.hpp> #include <boost/python/return_internal_reference.hpp> using namespace boost::python; tuple f(int x = 1, double y = 4.25, char const* z = "wow") { return make_tuple(x, y, z); } BOOST_PYTHON_FUNCTION_OVERLOADS(f_overloads, f, 0, 3) struct Y {}; struct X { Y& f(int x, double y = 4.25, char const* z = "wow") { return inner; } Y inner; }; BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS(f_member_overloads, f, 1, 3) BOOST_PYTHON_MODULE(args_ext) { def("f", f, f_overloads( args("x", "y", "z"), "This is f's docstring" )); class_<Y>("Y") ; class_<X>("X", "This is X's docstring") .def("f1", &X::f, f_member_overloads( args("x", "y", "z"), "f's docstring" )[return_internal_reference<>()] ) ; } </pre> <p>Revised  15 April, 2003  </p> <p><i>© Copyright <a href= "http://www.boost.org/people/dave_abrahams.htm">Dave Abrahams</a> 2002.</i></p> </body> </html>