Author: guido.van.rossum
Date: Thu Aug 2 18:48:17 2007
New Revision: 56672
Modified:
python/branches/py3k-struni/Lib/test/test_metaclass.py
python/branches/py3k-struni/Objects/typeobject.c
Log:
Add a default __prepare__() method to 'type', so it can be called
using super(). (See recent conversation on python-3000 with Talin
and Phillip Eby about PEP 3115 chaining rules.)
Modified: python/branches/py3k-struni/Lib/test/test_metaclass.py
==============================================================================
--- python/branches/py3k-struni/Lib/test/test_metaclass.py (original)
+++ python/branches/py3k-struni/Lib/test/test_metaclass.py Thu Aug 2
18:48:17 2007
@@ -207,6 +207,29 @@
kw: [('other', 'booh')]
>>>
+The default metaclass must define a __prepare__() method.
+
+ >>> type.__prepare__()
+ {}
+ >>>
+
+Make sure it works with subclassing.
+
+ >>> class M(type):
+ ... @classmethod
+ ... def __prepare__(cls, *args, **kwds):
+ ... d = super().__prepare__(*args, **kwds)
+ ... d["hello"] = 42
+ ... return d
+ ...
+ >>> class C(metaclass=M):
+ ... print(hello)
+ ...
+ 42
+ >>> print(C.hello)
+ 42
+ >>>
+
"""
__test__ = {'doctests' : doctests}
Modified: python/branches/py3k-struni/Objects/typeobject.c
==============================================================================
--- python/branches/py3k-struni/Objects/typeobject.c (original)
+++ python/branches/py3k-struni/Objects/typeobject.c Thu Aug 2 18:48:17 2007
@@ -2200,11 +2200,21 @@
return list;
}
+static PyObject *
+type_prepare(PyObject *self, PyObject *args, PyObject *kwds)
+{
+ return PyDict_New();
+}
+
static PyMethodDef type_methods[] = {
{"mro", (PyCFunction)mro_external, METH_NOARGS,
PyDoc_STR("mro() -> list\nreturn a type's method resolution order")},
{"__subclasses__", (PyCFunction)type_subclasses, METH_NOARGS,
PyDoc_STR("__subclasses__() -> list of immediate subclasses")},
+ {"__prepare__", (PyCFunction)type_prepare,
+ METH_VARARGS | METH_KEYWORDS | METH_CLASS,
+ PyDoc_STR("__prepare__() -> dict\n"
+ "used to create the namespace for the class statement")},
{0}
};
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