pygccxml-development

[pygccxml-development] Exposing boost::python::list

[Scott S. <sc...@bi...>]

Hi,

I'd like to have a class which as a boost::python::list as a public 
attribute.  I know that gccxml cannot parse boost/python.hpp, so given a 
suggestion on the mailing list archives, I have done the following:

#pragma once
#ifndef __GCCXML__
#include <boost/python.hpp>
typedef boost::python::list list;
#else
class list;
#endif

class MyClass {
   public:
     list * mylist;
};

MyClass::MyClass()
{
   mylist = new boost::python::list();
   mylist.append(1);
}
MyClass::~MyClass()
{
   delete mylist;
}

Py++ is able to create the bindings and it compiles fine.  However, when 
accessing the 'mylist' attribute in python, I'm seeing the following 
behavior:

>>> print type(myclass.mylist)

>>> print type(myclass.mylist)
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
TypeError: cannot create weak reference to 'list' object
>>> print type(myclass.mylist)
Fatal Python error: GC object already tracked
Aborted

I think I'm going about this the wrong way, but am unsure of the proper 
way.  Would this be a use case for the 'inserting_code' functionality of 
py++?

Thank you!

Scott

Re: [pygccxml-development] Exposing boost::python::list

[Scott S. <sc...@bi...>]

As a follow on, I did get this to work by using an actual list, and not a 
pointer to one.  So the pseudocode becomes:

#pramga once
#ifndef __GCCXML__
#include <boost/python.hpp>
typedef boost::python::list list;
#else
class list {};
#endif

class MyClass {
   public list mylist;
   MyClass() { mylist.append(1); }
};

Then in python, I have no problems:

>>> mc.mylist
[1]
>>> mc.append(2)
>>> mc.mylist
[1,2]

Thanks,

Scott


On Mon, 1 Aug 2011, Scott Sturdivant wrote:

> Hi,
>
> I'd like to have a class which as a boost::python::list as a public 
> attribute.  I know that gccxml cannot parse boost/python.hpp, so given a 
> suggestion on the mailing list archives, I have done the following:
>
> #pragma once
> #ifndef __GCCXML__
> #include <boost/python.hpp>
> typedef boost::python::list list;
> #else
> class list;
> #endif
>
> class MyClass {
>  public:
>    list * mylist;
> };
>
> MyClass::MyClass()
> {
>  mylist = new boost::python::list();
>  mylist.append(1);
> }
> MyClass::~MyClass()
> {
>  delete mylist;
> }
>
> Py++ is able to create the bindings and it compiles fine.  However, when 
> accessing the 'mylist' attribute in python, I'm seeing the following 
> behavior:
>
>>>> print type(myclass.mylist)
>
>>>> print type(myclass.mylist)
> Traceback (most recent call last):
>  File "<stdin>", line 1, in <module>
> TypeError: cannot create weak reference to 'list' object
>>>> print type(myclass.mylist)
> Fatal Python error: GC object already tracked
> Aborted
>
> I think I'm going about this the wrong way, but am unsure of the proper way. 
> Would this be a use case for the 'inserting_code' functionality of py++?
>
> Thank you!
>
> Scott
>

Re: [pygccxml-development] Exposing boost::python::list

[Roman Y. <rom...@gm...>]

Thank you for problem & solution contribution :-)

On Tue, Aug 2, 2011 at 11:31 PM, Scott Sturdivant <sc...@bi...> wrote:
> As a follow on, I did get this to work by using an actual list, and not a
> pointer to one.  So the pseudocode becomes:
>
> #pramga once
> #ifndef __GCCXML__
> #include <boost/python.hpp>
> typedef boost::python::list list;
> #else
> class list {};
> #endif
>
> class MyClass {
>   public list mylist;
>   MyClass() { mylist.append(1); }
> };
>
> Then in python, I have no problems:
>
>>>> mc.mylist
> [1]
>>>> mc.append(2)
>>>> mc.mylist
> [1,2]
>
> Thanks,
>
> Scott
>
>
> On Mon, 1 Aug 2011, Scott Sturdivant wrote:
>
>> Hi,
>>
>> I'd like to have a class which as a boost::python::list as a public
>> attribute.  I know that gccxml cannot parse boost/python.hpp, so given a
>> suggestion on the mailing list archives, I have done the following:
>>
>> #pragma once
>> #ifndef __GCCXML__
>> #include <boost/python.hpp>
>> typedef boost::python::list list;
>> #else
>> class list;
>> #endif
>>
>> class MyClass {
>>  public:
>>    list * mylist;
>> };
>>
>> MyClass::MyClass()
>> {
>>  mylist = new boost::python::list();
>>  mylist.append(1);
>> }
>> MyClass::~MyClass()
>> {
>>  delete mylist;
>> }
>>
>> Py++ is able to create the bindings and it compiles fine.  However, when
>> accessing the 'mylist' attribute in python, I'm seeing the following
>> behavior:
>>
>>>>> print type(myclass.mylist)
>>
>>>>> print type(myclass.mylist)
>> Traceback (most recent call last):
>>  File "<stdin>", line 1, in <module>
>> TypeError: cannot create weak reference to 'list' object
>>>>> print type(myclass.mylist)
>> Fatal Python error: GC object already tracked
>> Aborted
>>
>> I think I'm going about this the wrong way, but am unsure of the proper way.
>> Would this be a use case for the 'inserting_code' functionality of py++?
>>
>> Thank you!
>>
>> Scott
>>
>
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