Python.boost学习笔记（4）

标签：boost

这一章首先通过一个封装简单的类来讲解如何封装类的constructor, method和data member. 

#include <boost/python.hpp>
#include <iostream>
using namespace boost::python; 

class animal
{
public:
  
  animal()
  {
    myLanguage="";
  };
  animal(std::string language)
  {
    myLanguage=language;
  };
  std::string get()
  {
    return myLanguage;
  }
  std::string myLanguage;
};
BOOST_PYTHON_MODULE(cry)
{
  class_<animal>("animal")
    .def(init<std::string>()) // wrap for multipole constructors
    .def("get",&animal::get)
    .def_readonly("language", &animal::myLanguage); // or set it as def_readwrite, note: for private member, we cannot wrap it here
}

编译运行测试：

Python 2.7.5 (default, Nov  3 2014, 14:26:24) 
[GCC 4.8.3 20140911 (Red Hat 4.8.3-7)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import cry
>>> a=cry.animal()
>>> b=cry.animal("hello")
>>> print a.get()

>>> print b.get()
hello
>>> a.language
''
>>> b.language
'hello'
>>> b.language='test'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: can't set attribute
>>> 

把上面的例子稍微做修改

#include <boost/python.hpp>
#include <iostream>
using namespace boost::python; 

class animal
{
public:
  
  animal()
  {
    myLanguage="";
  };
  animal(std::string language)
  {
    myLanguage=language;
  };
  std::string get()
  {
    return myLanguage;
  }
protected:
  std::string myLanguage;
};

class dog :public animal
{
public:
  
  dog()
  {
    myLanguage="bak bak";
  };
  dog(std::string language)
    :animal(language)
  {
  };
};

void myCry(animal* it)
{
  std::cout<<it->get()<<std::endl;
}

BOOST_PYTHON_MODULE(cry)
{
  class_<animal>("animal")
    .def(init<std::string>())
    .def("get",&animal::get);
  class_<dog, bases<animal> >("dog")
    .def(init<std::string>());
  def("myCry",myCry);
}

class_<dog, bases<animal> >("dog")
    .def(init<std::string>());

Python 2.7.5 (default, Nov  3 2014, 14:26:24) 
[GCC 4.8.3 20140911 (Red Hat 4.8.3-7)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import cry
>>> a=cry.animal()
>>> b=cry.dog()
>>> myCry(a)
>>> cry.myCry(a)

>>> cry.myCry(b)
bak bak

那么再做简单的修改：

#include <boost/python.hpp>
#include <iostream>
using namespace boost::python; 

class animal
{
public:
  
  virtual std::string get()
  {
    return "Virtual animal, not implemented";
  }
  virtual ~animal(){};
};

class dog :public animal
{
public:
  virtual std::string get()
  {
    return "bak bak";
  }
  virtual ~dog(){};
};

// wrapper for animal
class animalWrap: public animal,public wrapper<animal>
{
public:
  std::string get()
  {
    if (override get=this->get_override("get"))
      return get();
    return animal::get();
  }
  std::string default_get()
  {
    return this->animal::get();
  }
};

void myCry(animal* it)
{
  std::cout<<it->get()<<std::endl;
}
BOOST_PYTHON_MODULE(cry)
{
  class_<animalWrap,boost::noncopyable>("animal")
    .def("get",&animal::get,&animalWrap::default_get);
  class_<dog, bases<animal> >("dog");
  def("myCry",myCry);
}

现在把get作为虚函数，返回string各不相同。 其中单独写的wrapper:

// wrapper for animal
class animalWrap: public animal,public wrapper<animal>
{
public:
  std::string get()
  {
    if (override get=this->get_override("get"))
      return get();
    return animal::get();
  }
  std::string default_get()
  {
    return this->animal::get();
  }
};

在boost wrapper里面两个都要wrap

 class_<animalWrap,boost::noncopyable>("animal")
    .def("get",&animal::get,&animalWrap::default_get);

注意class_后面放的是wrap class name,并且加了个不知为什么的boost::noncopyable, 后面两个我们wrapper里都定义的function都放进去。

编译后在python中定义一个叫做cat的animal的子类，通过myCry来检测是否像预期一样的工作

>>> from cry import *
>>> a=animal()
>>> b=dog()
>>> class cat(animal):
...     def get(self):
...             return "miao miao"
... 
>>> c=cat()
>>> myCry(a)
Virtual animal, not implemented
>>> myCry(b)
bak bak
>>> myCry(c)
miao miao
>>> 

Python.boost学习笔记（4）

标签：boost

原文地址：http://blog.csdn.net/ststns/article/details/43150821