On 2 June 2011 23:13, Robert Bradshaw <rober...@math.washington.edu> wrote: > On Thu, Jun 2, 2011 at 2:03 PM, mark florisson > <markflorisso...@gmail.com> wrote: > >>>>> If anyone is assigning a Cython function to an object and then using >>>>> it they're counting on the current non-binding behavior, and it will >>>>> break. The speed is probably a lesser issue, which is what benchmarks >>>>> are for. >>>> >>>> If you're binding functions to classes without expecting it to ever >>>> bind, you don't really have bitching rights when stuff breaks later >>>> on. You should have been using staticmethod() to begin with. And we >>>> never said that our functions would never bind :) >>> >>> No, you're assigning it to an object, counting on being able to call >>> it later on. E.g. the following is legal (though contrived in this >>> example): >>> >>> sage: class A: >>> ....: pass >>> ....: >>> sage: a = A() >>> sage: a.foo = max >>> sage: a.foo([1,2,3]) >>> 3 >>> >>> If instead of len, it was one of our functions, then it would be bad >>> to suddenly change the semantics, because it could still run but >>> produce bad answers (e.g. if we had implemented max, suddenly a would >>> be included in the comparison). This is why I proposed raising an >>> explicit error as an intermediate step. >>> >>> If we don't promise anything, the contract is whatever the code does. >>> That's the problem with not having a specification (which would be >>> really nice, but is a lot of work). >> >> Functions on objects never get bound, they only get bound if they are >> on the class. So your code would still work with binding functions. > > True. It would still break "A.foo = max" though. I'm not saying we > should support or encourage this, but lets break it hard before we > break it subtly.
Again, such code is highly fragile and frankly incorrect to begin with, as it's based on the assumption that "Cython functions" never get bound. Getting functions (defined outside of class bodies) to bind in classes is a feature, I sometimes found myself to want it. So basically an error would be fine, but it would prevent normal usage as we have it in Python. > - Robert > _______________________________________________ > cython-devel mailing list > cython-devel@python.org > http://mail.python.org/mailman/listinfo/cython-devel > _______________________________________________ cython-devel mailing list cython-devel@python.org http://mail.python.org/mailman/listinfo/cython-devel
