Boost C++ Libraries

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Boost.Python

Header <boost/python/args.hpp>

Contents

Introduction
keyword-expressions
Classes
class arg
class arg synopsis
class arg constructor
class arg template operator =
Keyword-expression operator ,
Functions (deprecated)
args(...)
Example(s)

Introduction

Supplies a family of overloaded functions for specifying argument keywords for wrapped C++ functions.

keyword-expressions

A keyword-expression results in an object which holds a sequence of ntbses, 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

Classes

class arg;

The objects of class arg are keyword-expressions holding one keyword ( size one )

Class arg synopsis

namespace boost { namespace python
{
        struct arg 
        {
          template <class T>
                  arg &operator = (T const &value);
          explicit arg (char const *name){elements[0].name = name;}
        };

}}

Class arg constructor

arg(char const* name);
Requires: The argument must be a ntbs.
Effects: Constructs an arg object holding a keyword with name name.

Class arg operator =

template <class T> arg &operator = (T const &value);
Requires: The argument must convertible to python.
Effects: Assigns default value for the keyword.
Returns: Reference to this.

Keyword-expression operator ,

      keyword-expression operator , (keyword-expression, const arg &kw) const
      keyword-expression operator , (keyword-expression, const char *name) const;
Requires: The argument name must be a ntbs.
Effects: Extends the keyword-expression argument with one more keyword.
Returns: The extended keyword-expression.

Functions (deprecated)

args(...)

  unspecified1 args(char const*);
    unspecified2 args(char const*, char const*);
       .
       .
       .
    unspecifiedN args(char const*, char const*, ... char const*);

Requires: Every argument must be a ntbs.
Returns: an object representing a keyword-expression encapsulating the arguments passed.

Example

#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 ) 
            );
}

Revised 01 August, 2003

© Copyright Dave Abrahams 2002-2003.