On 5 Jun, 2007, at 22:00, Heikki Toivonen wrote:
There are lots and lots of cases in our code where we use len() to
determine if a collection, list, tuple, string etc. is empty or not.
This is wasteful; it is much better to check if the item in
question is
empty. Python even has a special method for it, __nonzero__.
Also, doing a len() on some objects causes side effects to happen that
you may not want, like creating repository indexes (of course avoiding
index creation in one spot will likely just move it to another spot
which you may not want).
In case of misunderstanding:
On IRC today, Andi pointed out that the repository never creates
indexes unless you explicitly ask it to. There is, however Chandler
Collection code that creates repository indexes in __len__, which is
what Heikki was talking about.
--Grant
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