On Feb 1, 2010, at 6:37 AM, Dag Sverre Seljebotn wrote: > Stefan Behnel wrote: >> Dag Sverre Seljebotn, 25.01.2010 10:17: >> >>> Stefan Behnel wrote: >>> >>>>> [...] why not just represent a borrowed reference as a pointer? >>>>> So you could write >>>>> >>>>> cdef list some_list = [] >>>>> cdef list* borrowed_ref = some_list >>>>> >>>>> and borrowed_ref would be a non-refcounted pointer to a Python >>>>> list. >>>>> Assignments back to a normal reference would be allowed: >>>>> >>>>> cdef list my_list = borrowed_ref # increfs the pointer >>>>> >>>>> After all, a non-refcounted reference to a Python object is not >>>>> more than a >>>>> bare pointer to a well-defined Python builtin/extension type >>>>> (including >>>>> "object*"). >>>>> >>> Well, there's the drawback of making the language more >>> complicated, and >>> also I think the notation is confusing -- plain "object" is not by >>> value, and "object*" is not a pointer to an "object", so to speak. >>> >> >> I was trying to let the syntax emphasise that it *is* a pointer, >> not a >> reference. A reference is special in Cython in that it handles ref- >> counting >> for it. A pointer just behaves like any other pointer in the >> language. >> >> I agree that it's not flawless, but I think it makes sense and is >> unambiguous. >> > Let me put it this way: To me, "object*" somehow indicates PyObject**, > since "object" is PyObject*. I find it confusing that "object" and > "object*" are at the same "indirection level", so to speak. > > Also, would > > cdef object* x = ... > print x[0] > > do a getitem on x, or returned a reference-counted copy of x? Not easy > to guess from the syntax alone. > > Assuming a getitem (as that's a useful operation and the other is > already served by <object>x), one is then inconsistent with everywhere > else the *-notation is used. > > I'd be fine with almost any kind of syntax which is a superset of the > current syntax -- "cdef nonmanaged object x", you name it. The problem > with "object*" is that it is not immediately obvious to a reader > with a > brief knowledge of Cython that it is fundamentally different from > "int*". > > This is a very subjective matter though.
My impressions are similar. A "borrowed" type modifier is fine by me. - Robert _______________________________________________ Cython-dev mailing list [email protected] http://codespeak.net/mailman/listinfo/cython-dev
