1[section boost/python/args.hpp] 2[section Introduction] 3Supplies a family of overloaded functions for specifying argument keywords for wrapped C++ functions. 4[section keyword-expressions] 5A keyword-expression results in an object which holds a sequence of [link ntbs]\ es, and whose type encodes the number of keywords specified. The keyword-expression may contain default values for some or all of the keywords it holds 6[endsect] 7[endsect] 8[section Class `arg`] 9The objects of class arg are keyword-expressions holding one keyword ( size one ) 10`` 11namespace boost { namespace python 12{ 13 struct arg 14 { 15 template <class T> 16 arg &operator = (T const &value); 17 explicit arg (char const *name){elements[0].name = name;} 18 }; 19 20}} 21`` 22[endsect] 23[section Class `arg` constructor] 24``arg(char const* name);`` 25[variablelist 26[[Requires][The argument must be a [link ntbs].]] 27[[Effects][Constructs an arg object holding a keyword with name name.]] 28] 29[endsect] 30[section Class `arg` operator=] 31``template <class T> arg &operator = (T const &value);`` 32[variablelist 33[[Requires][The argument must convertible to python.]] 34[[Effects][Assigns default value for the keyword.]] 35[[Returns][Reference to `this`.]] 36] 37[endsect] 38[section Keyword-expression operator,] 39`` 40keyword-expression operator , (keyword-expression, const arg &kw) const 41keyword-expression operator , (keyword-expression, const char *name) const; 42`` 43[variablelist 44[[Requires][The argument name must be a [link ntbs].]] 45[[Effects][Extends the keyword-expression argument with one more keyword.]] 46[[Returns][The extended keyword-expression.]] 47] 48[endsect] 49[section Example] 50`` 51#include <boost/python/def.hpp> 52using namespace boost::python; 53 54int f(double x, double y, double z=0.0, double w=1.0); 55 56BOOST_PYTHON_MODULE(xxx) 57{ 58 def("f", f, (arg("x"), "y", arg("z")=0.0, arg("w")=1.0)); 59} 60`` 61[endsect] 62[endsect] 63