Boost.Python

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Introduction

Classes

Class Template to_python_indirect

Class Template to_python_indirect synopsis

Class Template to_python_indirect observer functions

Class Template to_python_indirect static functions

Example

Introduction

Classes

Class template to_python_indirect

Class template to_python_indirect converts objects of its first argument type to python as extension class instances, using the ownership policy provided by its 2nd argument.

to_python_indirect Requirements
In the table below, x denotes an object of type T, h denotes an object of type boost::python::objects::instance_holder*, and p denotes an object of type U*.

Parameter	Requirements	Description
T	Either U cv& (where cv is any optional cv-qualification) or a Dereferenceable type such that *x is convertible to U const&, where U is a class type.	A type deferencing a C++ class exposed to Python using class template class_.
MakeHolder	h = MakeHolder::execute(p);	A class whose static execute() creates an instance_holder.

Instantiations of to_python_indirect are models of ResultConverter.

Class template to_python_indirect synopsis

namespace boost { namespace python
{
  template <class T, class MakeHolder>
  struct to_python_indirect
  {
     static bool convertible();
     PyObject* operator()(T ptr_or_reference) const;
   private:
     static PyTypeObject* type();
  };
}}

Class template to_python_indirect observers

PyObject* operator()(T x) const;

Requires: x refers to an object (if it is a pointer type, it is non-null). convertible() == true.

Effects: Creates an appropriately-typed Boost.Python extension class instance, uses MakeHolder to create an instance_holder from x, installs the instance_holder in the new extension class instance, and returns a pointer to it.

Class template to_python_indirect statics

bool convertible();

struct make_reference_holder
{
   typedef boost::python::objects::instance_holder* result_type;
   template <class T>
   static result_type execute(T* p)
   {
      return new boost::python::objects::pointer_holder<T*, T>(p);
   }
};

struct reference_existing_object
{
   // metafunction returning the ResultConverter
   template <class T>
   struct apply
   {
      typedef boost::python::to_python_indirect<T,make_reference_holder> type;
   };
};