[pypy-svn] r64247 - pypy/trunk/pypy/doc

[cfbolz at codespeak.net]

Author: cfbolz
Date: Fri Apr 17 12:52:00 2009
New Revision: 64247

Modified:
   pypy/trunk/pypy/doc/cpython_differences.txt
Log:
another cpython difference


Modified: pypy/trunk/pypy/doc/cpython_differences.txt
==============================================================================
--- pypy/trunk/pypy/doc/cpython_differences.txt	(original)
+++ pypy/trunk/pypy/doc/cpython_differences.txt	Fri Apr 17 12:52:00 2009
@@ -46,13 +46,23 @@
 for most of PyPy's garbage collectors.
 This is most visible in the default repr: a typical PyPy object can
 pretend to be located ``at 0x00000009``.  This is just its ``id()``, not
-its real address (because the physical address can change).
+its real address (because the physical address can change for some GCs). Calling
+``id`` a lot can lead to performance problem.
 
 Note that if you have a long chain of objects, each with a reference to
 the next one, and each with a __del__, PyPy's GC will perform badly.  On
 the bright side, in most other cases, benchmarks have shown that PyPy's
 GCs perform much better than CPython's.
 
+Another difference is that if you add a ``__del__`` to an existing class it will
+not be called::
+
+    >>>> class A(object):
+    ....     pass
+    ....
+    >>>> A.__del__ = lambda self: None
+    __main__:1: RuntimeWarning: a __del__ method added to an existing type will not be called
+
 
 Subclasses of built-in types
 ----------------------------