[C++-sig] [pybindgen] references?

[Gustavo Carneiro]

2008/11/3 Stefan Seefeld <seefeld at sympatico.ca>

> Alan Baljeu wrote:
>
>> I just read the tutorial page on pybindgen, but it doesn't talk about
>> reference types.  99% of my C++ code involves passing around things like
>> foo&, so this is significant to me.  How is it done?
>>
>>
>
> If you need fine-grained control about argument passing policies (as soon
> as you need reference-semantics, you have to be careful about lifetime
> management, for example), you are better off writing boost.python bindings
> manually, I would suggest.


I know that you're thinking about the custodian_and_ward policy of
boost.python, but pybindgen also supports it.  For example:

class SomeObject
{
[...]
    Foobar* get_foobar_with_self_as_custodian ();
    Foobar* get_foobar_with_other_as_custodian (const SomeObject *other);
    void set_foobar_with_self_as_custodian (Foobar *foobar);
};


Is wrapped by pybindgen code:

    SomeObject = mod.add_class('SomeObject', allow_subclassing=True)
   [...]
    SomeObject.add_method('get_foobar_with_self_as_custodian',
                          retval('Foobar*', custodian=0), [])
    SomeObject.add_method('get_foobar_with_other_as_custodian',
                          retval('Foobar*', custodian=1),
                          [param('SomeObject*', 'other',
transfer_ownership=False)])
    SomeObject.add_method('set_foobar_with_self_as_custodian',
retval('void'),
                          [param('Foobar*', 'foobar', custodian=0)])

[excerpt from the pybindgen unit tests]

Although I personally dislike this sort of practice; I would hate working
with APIs this complicated even in C++.

-- 
Gustavo J. A. M. Carneiro
INESC Porto, Telecommunications and Multimedia Unit
"The universe is always one step beyond logic." -- Frank Herbert
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