[C++-sig] [boost.python] How can I wrap operator==?

[Roman Yakovenko]

On Wed, Jan 13, 2010 at 8:57 AM, blp330 <blp330 at msn.com> wrote:
>
> Um... Sorry, I mean I have a class Document, which defined
>
> class Document
> {
> public:
>  ....
>
>  bool operator==(const Document& other) const
>  {
>  return Compare(other);
>  }
> };
>
> It simply call Compare method, I need to something more when I use it in
> python code but I don't want to change my Document class implementation
> because it can be used by other language that do not need extra code.
>
> Py++ generates:
> Document_exposer.def( bp::self == bp::self );
>
> For other Document method I can change Py++ generated code to do something
> more, for example:
> Py++:
>   {
>            typedef ::StringPtr ( ::Document::*Thumb_function_type )(
> int,int ) const;
>
>            Document_exposer.def(
>                "Thumb"
>                //, Thumb_function_type( &::Document::Thumb )
>                , &Document__ThumbWrap
>                , ( bp::arg("width"), bp::arg("height") ) );
>
>        }
> I can define a Document__ThumbWrap function to write my extra code in it.
>
> But operator==, I don't know how to do that.
> I can't simply change
> Document_exposer.def( bp::self == bp::self );
> to
> Document_exposer.def(
>     bp::self == bp::self
>     , &Document__EqualWrap
>  );
> to write my extra code in Document__EqualWrap.

If I understand you right, you need:

1. define new global function, which takes Document& as the first argument

bool Document_EqualWrap( const Document& x, const Document& y ){...}

2. Expose it:

...
.def( "__eq__", &Document_EqualWrap )

Is not the working code, but it should give you a direction.

-- 
Roman Yakovenko
C++ Python language binding
http://www.language-binding.net/