Re: [Python-Dev] special method lookup: how much do we care?

Benjamin Peterson wrote:

2009/5/8 Daniel Stutzbach :

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On Fri, May 8, 2009 at 6:14 PM, Benjamin Peterson wrote:

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Normally special methods use slots of the PyTypeObject struct. typeobject.c looks up all those methods on Python classes correctly. In the case of __enter__ and __exit__, the compiler generates bytecode to look them up, and that bytecode use PyObject_Getattr. Would this problem apply to all special methods that don't use a slot in PyTypeObject, then? I know of several other examples:

Yes. I didn't think of those.

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__reduce__ __setstate__ __reversed__ __length_hint__ __sizeof__

(unless I misunderstand the definition of "special methods", which is possible)

__reversed__, at least, is called by the reversed() builtin, so there is no LOAD_ATTR k (__reversed__) byte code. So for that, the problem is reduced to accessing type(it).__reversed__ without going thru type(it).__getattribute__. I would think that a function that did that would work for the others on the list (all 4?) that also have no LOAD_ATTR bytecode. Would a modified version of object.__getattribute__ work? tjr