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no singletons, please (was Re: an example Re: Connecting to running win32com server)

Glyph Lefkowitz glyph at no.spam
Thu Oct 12 15:51:57 EDT 2000 
"Alex Martelli" <aleaxit at yahoo.com> writes:

> it's often best to *decouple identity and state*, by having
> many objects (different identities) *sharing state*, rather
> than trying to ensure the state-sharing happens through all
> object being one (having the same identity).

I'm not quite clear on what you mean by that.  Do you mean something like

class FooBar:
  MyState = {}

  def __init__(self):
    self.__dict__ = MyState

What good would that do?
  

> This applies to COM (in any language), but also outside of it.
> 
> "Same-Identity" can be a heavy burden to carry around when
> all one really wants to ensure is "Same-State"... which is
> most of the time when one starts thinking "Singleton"!

And besides, "singleton" is just the 90's way of saying "Global
Variable", since Global Variables are bad style for a variety of
reasons, but "Singleton" is a design pattern, and therefore must be
good... sheesh

When I have something that looks like a "singleton", I almost always
store it as a bunch of global state in the module that it's related to
rather than devoting a proper instance to it.

-- 
Glyph Lefkowitz
Professional -- Software Engineer,  Origin Systems
Amateur      -- Computer Scientist, Twisted Matrix Enterprises
(My opinions are my own and do not reflect in any way on the policies
or practices of my employer, etcetera etcetera.)
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