[Zope-dev] implementing zope.component 4.0

[Martijn Faassen]

Gary Poster wrote:
> Then to the multiadapter concern I raised, all my real-world examples
> of adapters are to adapt one object so it can be used in a certain
> way (to integrate with another kind of object).  Power adapters, for
> instance, adapt a plug (required interface) so it can plugged in to
> the wall (output interface).  Is there a common real-world example of
> this for "multiadapters"?

It's a good question. Plugging a power cord in on both ends? :)
Slightly more seriously, a lego brick connecting to multiple other 
bricks? But that isn't a good enough answer to that question.

>>> 3) I also think that "utility" is a bad name.  Is "singleton" two
>>>  letters too long?  If it is, I mind "utility" less than I mind
>>> "adapter".
>> I don't understand this. For me a singletons is (sic) a highly
>> specific programming term whereas adapters and utilities,
>> especially in the way we refer to them, are not so domain specific.
>
> Turned around, people know the term "singleton" and they do not know
> the terms "adapters" and "utilities".  "singletons" describe the huge
> majority of how we use these things.  It's something less to explain.
> Making comprehension quicker is very valuable to me.

I don't like the word singleton very much either. Singleton in the 
Design Patterns book has a very particular implementation that is 
criticized by a lot of developers and in particular that particular 
pattern is very uncommon in the Python world (people just use globals). 
I think introducing the term would pull in all that baggage to a 
newcomer. Just type in 'singleton' in Google and you'll get the 
wikipedia definition:

   In software engineering, the singleton pattern is a design pattern
   that is used to restrict instantiation of a class to one object.

Utility classes are *not* restricted to a single instantiation. Now we 
can argue successfully that's an extension of the singleton principle, 
but then we've lost a lot of people already who thought they knew (or 
went to lookup) what the word "singleton" means.

Regards,

Martijn