"Frans Englich" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
Hello,
[...]
What the code attempts to do is implementing a, to the API user,
transparent
memory-saver by ensuring that no more than one instance of the class foo
exists for a particular id. E.g, the user can simply "create" an instance
and
if one not already exists, it is created.
In other words, you're trying to create a singleton. In general,
singletons are frowned on these days for a number of reasons,
not least because of the difficulty of testing them.
First of all; am I approaching the goal with the right solution?
No. In all Python releases since 2.2, the correct way of doing this is to
use the __new__() method. Unfortunately, the only place it is documented
is here:
http://www.python.org/2.2.3/descrintro.html
and here:
http://users.rcn.com/python/download/Descriptor.htm
The first reference contains an example of how to do
a singleton: simply search on the word Singleton.
John Roth
Cheers,
Frans
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