Greetings. 1. First, about a bug (Boost 1.33.0, MSVC 7.1): After exporting void test1( const char * ) { } void test2( std::string ) { } we get an assertion failure _BLOCK_TYPE_IS_VALID( ... ) on std::strings longer than a dozen of characters: test1( 'hello' ) # OK test2( 'hello' ) # OK test1( 'how do you do, tell me please' ) # OK test2( 'how do you do, tell me please' ) # failure 2a. From `Exposing Classes' tutorial section: "If Base is polymorphic, Derived objects which have been passed to Python via a pointer or reference to Base can be passed where a pointer or reference to Derived is expected." Now, that's a great feature, but I couldn't help noticing that what Boost.Python actually does, is even more useful: not only such pointers can be passed instead of Derived ones, but their Python counterparts _are_ fully qualified Derived representations, with all the methods and everything. Probably worth mentioning in dox that way. 2b. Now, suppose we have one more derived class: class Base { ... }; class Derived: public Base { ... }; class HiddenImplementation: public Derived { ... }; with Derived being no more than an interface. Naturally, we don't want to export HiddenImplementation to Python, but still want to retain automatic conversions from Base* to Derived* whenever pointer to HiddenImplementation object is passed to Python. Any way to do this? Without hack-ins? I was able to trick the system by defining the fake empty implemetation class class HiddenImplementation: public Derived { }; right before the BOOST_PYTHON_MODULE and exporting it out there, but this kind of `solution' really annoys me. And I don't understand why it works, either :) . Oh, and it's only a partial solution, too: we do not have to access the real implementation class, but we still have to export something. Comments? -- TIA, Vladimir mailto:ardatur@mail.ru