Hi Lisandro, Lisandro Dalcin schrieb am 27.09.2017 um 14:42: > $ cython --version > Cython version 0.27 > > $ cat tmp.pyx > def f() -> (list, list): > return [], [] > > $ cython tmp.pyx > > Error compiling Cython file: > ------------------------------------------------------------ > ... > def f() -> (list, list): > ^ > ------------------------------------------------------------ > > tmp.pyx:1:12: C struct/union member cannot be a Python object > > Error compiling Cython file: > ------------------------------------------------------------ > ... > def f() -> (list, list): > ^ > ------------------------------------------------------------ > > tmp.pyx:1:12: C struct/union member cannot be a Python object
Yes, I noticed that, too. It's a bit annoying. PEP 484 would spell this using the "Tuple" type, i.e. "Tuple[list, list]", or even something like "Tuple[List[Any], List[Any]]". The problem in Cython is that the syntax is reserved for C tuples, which are syntactically nicer structs. "(list, list)" is a struct with two member lists, but since structs do not support reference counting, this is illegal in Cython. The best way to resolve this for now is probably to ignore C tuples in function annotations entirely. At some point, Cython will have to learn to understand complex PEP-484 types like Tuple[]. Stefan _______________________________________________ cython-devel mailing list cython-devel@python.org https://mail.python.org/mailman/listinfo/cython-devel
