Mihail Konstantinov wrote:
Roman Yakovenko wrote:
It is not a good idea. Python string is immutable. May be you should
consider custom converter.
http://www.boost.org/doc/libs/1_37_0/libs/python/doc/v2/faq.html#custom_string
I don't see why it is not a good idea. I am nowhere accessing any string
derived classes in a mutable fashion, am I?
Also I have no option to change the class hierarchy. The code fragments I am
posting are simplified from a large project that I try to pythonify, reduced to
what I think is the cause of the problems. I want to avoid modifying the
underlying project under all circumstances.
You are attempting to make Python aware of the inheritance relationship
between std::string and your own class. That is what doesn't work, not
your own deriving from std::string.
In order to make 'bases<std::string>' work, you would have to export the
std::string class to Python first. But as that isn't what you actually
want, you may as well remove the 'bases<std::string>' from your code,
and instead rely on (implicit) conversion.
Can I modify the declaration inside BOOST_PYTHON_MODULE so that the implicit
conversion is recognized and the above call boost_ext.printme(b) succeeds?
Yes: http://www.boost.org/doc/libs/1_37_0/libs/python/doc/v2/implicit.html
This looks very helpful. But I don't understand the C++ module definition
example on that page. It ends with
implicitly_convertible<X,int>();
implicitly_convertible<int,X>();
}
I see that an int can be implicitly converted to X. But how can an X be
converted to an int? I can't believe that boost.python searches all implemented
functions to find that make_x is capable of converting an int to X?
I believe it simply expects an 'operator int ()' to be available in that
case.
Regards,
Stefan
--
...ich hab' noch einen Koffer in Berlin...
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