On Nov 15, 4:58 pm, Steve Howell <showel...@yahoo.com> wrote:
> On Nov 15, 4:03 pm, Christian Heimes <li...@cheimes.de> wrote:
>
> > Try this untested code:
>
> > class Spam(dict):
> > def __getitem__(self, key):
> > getitem = self.__dict__.get("__getitem__", dict.__getitem__)
> > return getitem(self, key)
> > [...]
>
> [I originally responded...] Not sure how this helps me, unless I am
> misunderstanding...
>
Ok, now I get where you were going with the idea. The following code
runs as expected. Even in pure testing mode, I would want to make it
a little more robust, but it illustrates the basic idea that you can
monitor just particular objects by overriding the class method to look
for an attribute on the instance before doing any special processing.
class MyDict(dict):
pass
dict1 = MyDict()
dict1['foo'] = 'bar'
dict2 = MyDict()
dict2['spam'] = 'eggs'
dict3 = MyDict()
dict3['BDFL'] = 'GvR'
def spy(dict):
def mygetitem(self, key):
if hasattr(self, '__SPYING__'):
value = self.__class__.__old_getitem__(self, key)
print 'derefing %s to %s on %s' % (key, value, self)
return value
if not hasattr(dict.__class__, '__HOOKED__'):
setattr(dict.__class__, '__old_getitem__',
dict.__class__.__getitem__)
setattr(dict.__class__, '__getitem__', mygetitem)
setattr(dict.__class__, '__HOOKED__', True)
dict.__SPYING__ = True
dict1['foo'] # not spied yet
spy(dict1) # this changes class and instance
dict1['foo'] # spied
dict2['spam'] # not spied
spy(dict3) # this only changes instance
dict3['BDFL'] # spied
dict2['spam'] # spied
Thanks, Christian!
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