[Boost-bugs] [Boost C++ Libraries] #6203: boost::python::api::object constructor failure

Subject: [Boost-bugs] [Boost C++ Libraries] #6203: boost::python::api::object constructor failure
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-12-03 11:38:21

#6203: boost::python::api::object constructor failure
-----------------------------------------------+----------------------------
 Reporter:  Johan Råde <johan.rade@…>          |       Owner:  rwgk   
     Type:  Bugs                               |      Status:  new    
Milestone:  To Be Determined                   |   Component:  Python 
  Version:  Boost 1.48.0                       |    Severity:  Problem
 Keywords:                                     |  
-----------------------------------------------+----------------------------
 Here is the C++ code for a Python extension module and a Python script
 that calls the module.
 Expected behavior when you run the script:
 {{{
 The script runs and produces the output "Hello, I'm Y!"
 }}}
 Observed behavior (with Boost 1.48.0, Python 2.7.2, MSVS 2010):
 {{{
 The script fails with the error message:

 Traceback (most recent call last):
   File "../TestHello/TestHello.py", line 12, in <module>
     y = Hello.create('Y')
 TypeError: No to_python (by-value) converter found for C++ type: class Y
 Press any key to continue . . .
 }}}

 I have also attached a zip file with the code as a solution for MSVS 2010
 and Python Tools for Visual Studio.

 Hello.cpp:
 {{{
 #include <string>
 #include <exception>
 #include <boost/noncopyable.hpp>
 #include <boost/python.hpp>

 using std::string;
 using boost::noncopyable;
 using boost::python::class_;
 using boost::python::def;

 class X : noncopyable {
 public:
     string hello() const { return "Hello, I'm X!"; }
 };

 class Y : noncopyable {
 public:
     string hello() const { return "Hello, I'm Y!"; }
 };

 class Z : noncopyable {
 public:
     string hello() const { return "Hello, I'm Z!"; }
 };

 PyObject* create(char c)
 {
     if(c == 'X')
         return boost::python::api::object(new X).ptr();
     else if(c == 'Y')
         return boost::python::api::object(new Y).ptr();
     else if(c == 'Z')
         return boost::python::api::object(new Z).ptr();
     else
         throw std::exception("The function argument must be 'X', 'Y' or
 'Z'.");
 }

 BOOST_PYTHON_MODULE(Hello)
 {
     class_<X, noncopyable>("X").def("hello", &X::hello);
     class_<Y, noncopyable>("Y").def("hello", &Y::hello);
     class_<Z, noncopyable>("Z").def("hello", &Z::hello);

     def("create", &create);
 }
 }}}

 Test.py:
 {{{
 import Hello
 y = Hello.create('Y')
 print(y.hello())
 }}}

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/6203>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.