Hi! I'd apreciate help with implementing pickling of classes with metaclasses.
I have a class MyPolyRing, such that type(MyPolyRing) is some metaclass that defines a __reduce__ method for MyPolyRing. I thought that, generally, pickling should work for any object O (where O might be a class) such that type(O).__reduce__(O) returns data that can be pickled. However, in my example (whith O=MyPolyRing), while type(O).__reduce__(O) can be pickled and O can be reconstructed "manually", pickling of O does not work: sage: f,L = type(MyPolyRing).__reduce__(MyPolyRing) sage: loads(dumps(type(MyPolyRing).__reduce__(MyPolyRing))) (Cached version of <built-in function _get_class_with_hash>, (<class '_home_king_SAGE_work_fast_hash_fast_hash_pyx_0.FastHashAndDynamicMetaclass'>, <class 'sage.rings.polynomial.polynomial_ring.PolynomialRing_field_with_category'>)) sage: loads(dumps(f))(*loads(dumps(L))) is MyPolyRing True sage: dumps(MyPolyRing) Traceback (most recent call last): ... PicklingError: Can't pickle <class 'sage.rings.polynomial.polynomial_ring.PolynomialRing_field_with_category_with_hash'>: attribute lookup sage.rings.polynomial.polynomial_ring.PolynomialRing_field_with_category_with_hash failed Hence, appparently I misunderstood the pickling protocol. What else is to provide, on top of a __reduce__ method of the type of the object? How can I find out what attribute is attempted to be looked up? Best regards, Simon -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
