Author: Armin Rigo <ar...@tunes.org>
Branch:
Changeset: r74607:dccc80a97cab
Date: 2014-11-20 11:22 +0100
http://bitbucket.org/pypy/pypy/changeset/dccc80a97cab/
Log: Update the doc: one difference with CPython disappeared, but there
are others more subtle ones.
diff --git a/pypy/doc/cpython_differences.rst b/pypy/doc/cpython_differences.rst
--- a/pypy/doc/cpython_differences.rst
+++ b/pypy/doc/cpython_differences.rst
@@ -205,23 +205,28 @@
The above is true both in CPython and in PyPy. Differences
can occur about whether a built-in function or method will
call an overridden method of *another* object than ``self``.
-In PyPy, they are generally always called, whereas not in
-CPython. For example, in PyPy, ``dict1.update(dict2)``
-considers that ``dict2`` is just a general mapping object, and
-will thus call overridden ``keys()`` and ``__getitem__()``
-methods on it. So the following code prints ``42`` on PyPy
-but ``foo`` on CPython::
+In PyPy, they are often called in cases where CPython would not.
+Two examples::
- >>>> class D(dict):
- .... def __getitem__(self, key):
- .... return 42
- ....
- >>>>
- >>>> d1 = {}
- >>>> d2 = D(a='foo')
- >>>> d1.update(d2)
- >>>> print d1['a']
- 42
+ class D(dict):
+ def __getitem__(self, key):
+ return "%r from D" % (key,)
+
+ class A(object):
+ pass
+
+ a = A()
+ a.__dict__ = D()
+ a.foo = "a's own foo"
+ print a.foo
+ # CPython => a's own foo
+ # PyPy => 'foo' from D
+
+ glob = D(foo="base item")
+ loc = {}
+ exec "print foo" in glob, loc
+ # CPython => base item
+ # PyPy => 'foo' from D
Mutating classes of objects which are already used as dictionary keys
_______________________________________________
pypy-commit mailing list
pypy-commit@python.org
https://mail.python.org/mailman/listinfo/pypy-commit
