[Cython] Expected errors of tests/errors/cdef_members_T517.pxd
robertwb at math.washington.edu
Sun Feb 27 04:16:37 CET 2011
On Sat, Feb 26, 2011 at 6:34 PM, W. Trevor King <wking at drexel.edu> wrote:
> On Sat, Feb 26, 2011 at 10:15:38AM -0800, Robert Bradshaw wrote:
>> On Sat, Feb 26, 2011 at 5:08 AM, W. Trevor King <wking at drexel.edu> wrote:
>> > The relevant lines from tests/errors/cdef_members_T517.pxd are:
>> > $ grep -n ^ tests/errors/cdef_members_T517.pyx
>> > ...
>> > 8:ctypedef struct Foo:
>> > 9: int i
>> > 10:
>> > 11:cdef class Bar:
>> > 12: cdef Foo foo0
>> > 13: cdef readonly Foo foo2
>> > 14: cdef public Foo foo1
>> > 15: pass
>> > ...
>> What's less clear is the behavior of
>> b = Bar()
>> b.foo1 = Foo(i=1)
>> b.foo1.i = 100
>> print b.foo1
>> saved = b.foo1
>> del b
>> print saved
> Is the problem choosing between:
> 1) Copy struct data into its own PyObject and let Python manage the
> 2) Pass around a pointer to Cython-managed struct data.
> I suppose I don't really know enough about how Cython handles this yet
> to really see the problem or be able to help with a solution ;).
Cython doesn't handle this yet--that's what we get to decide. Another
option would be to use weakrefs to implement
copy-on-owner-destruction, but that has even subtler corner semantics.
b = Bar()
b.foo1 = Foo(i=1)
first = b.foo1
second = b.foo1
first.i = 100
first.i = 200
I'm leaning towards (1) for ease and efficiency of implementation and
it's easier to explain in all cases.
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