On Tuesday 13 December 2016 15:57, Matthias Bussonnier wrote: [...] > I could of course write a function that try/except and return False/True > depending on the result, but that seem suboptimal as how can I know that the > TypeError does come from not being able to take a weak reference ? And not > from something else ?
Do you mean something like this? try: proxy = weakref.proxy(obj) except TypeError: proxy = None Where else could it come from? > The common Idiom in CPython, at the C layer seem to be > PyType_SUPPORTS_WEAKREFS(Py_TYPE(ob)). So I can (and did) write a C-extension > that expose such a function, but it does seem silly that no one else did that > before me, and that no one seemed to have encountered the problem before. > > So am I missing something ? Is such a function not useful ? Is there any > reason not to have it in the stdlib ? You could try raising a feature request on the bug tracker. -- Steven "Ever since I learned about confirmation bias, I've been seeing it everywhere." - Jon Ronson -- https://mail.python.org/mailman/listinfo/python-list