On Tue, 27 Jan 2009, Reckoner wrote:
> I'm not sure this is possible, but I would like to have
> a list of objects
>
> A=[a,b,c,d,...,z]
>
> where, in the midst of a lot of processing I might do something like,
>
> A[0].do_something_which_changes_the_properties()
>
> which alter the properties of the object 'a'.
>
> The trick is that I would like A to be mysteriously aware that
> something about the object 'a' has changed so that when I revisit A,
> I will know that the other items in the list need to be refreshed to
> reflect the changes in A as a result of changing 'a'.
>
> Even better would be to automatically percolate the subsequent changes
> that resulted from altering 'a' for the rest of the items in the list.
[...]
Interesting question.
Maybe this is too simple for your purpose (or maybe just wrong!), but could
you subclass list and give it an "update" method which keeps a dictionary of
the state of its members and/or calls another method that makes the
appropriate changes in the other members when a change occurs, something
like:
class SelfAwareList(list):
state_dict = {}
def update(self):
for i in self:
if i.state == 'some_condition':
self.do_stuff_to_other_members()
self.state_dict[i] = i.state
def do_stuff_to_other_members(self):
print 'doing stuff...'
?
You could manually call update() on the SelfAwareList instance after calling a
method on a SelfAwareList member, or even build it into the members' methods
so that it was automatic.
HTH,
John
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