Christian Heimes wrote:
Terry Reedy wrote:
One of the nice features of 3.0 is that differences between classes
defined in C and Python (other than speed) are mostly erased or hidden
from the view of a Python programmer.
However, there are still sometimes surprising and quite visible
differences between 'functions' written in C and Python. Can these be
better unified also?
In particular, built-in functions, in spite of of being labeled
'builtin_function_or_method', are not usable as methods because they
lack the __get__ method needed to bind function to instance.
Python is far too late in the release cycle to introduce a drastic
change.
Of course. I should have been clear that I was asking for 3.1.
> The issues has been discussed about half a year ago and we
decided against changing PyCFunction.
I did't remember that. Was it a permanent or provisional decision.
But it was a good thing that you've raises your concern. I totally
forgot about the new instancemethod type. My code is still in
classobject.c but it's not exposed to Python level. IIRC the
Pyrex/Cython guys are in need of such a feature.
Patch:
--- Python/bltinmodule.c (revision 66222)
+++ Python/bltinmodule.c (working copy)
@@ -2301,6 +2301,7 @@
SETBUILTIN("frozenset", &PyFrozenSet_Type);
SETBUILTIN("property", &PyProperty_Type);
SETBUILTIN("int", &PyLong_Type);
+ SETBUILTIN("instancemethod", &PyInstanceMethod_Type);
SETBUILTIN("list", &PyList_Type);
SETBUILTIN("map", &PyMap_Type);
SETBUILTIN("object", &PyBaseObject_Type);
Result:
$ ./python
Python 3.0b3+ (py3k:66222M, Sep 5 2008, 02:24:22)
[GCC 4.2.3 (Ubuntu 4.2.3-2ubuntu7)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> class Example:
... id = instancemethod(id)
...
>>> example = Example()
>>> example.id() == id(example)
True
I consider that 2nd best but it will solve the problem once one is aware
of it. I am thinking of suggesting a new paragraph for the Built-in
Functions sections warning of differences between built-in functions and
function instances.
Terry
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