[Tutor] Re: How do you share a method (function) among several objects?

[Xif]

Ok, so keeping getCells() as an external function makes sense.

But where exactly do you recommend I'd put it?

In a seperate module, like I currently do, even though it's going to be 
the only piece of code contained inside that module?

Xif

Pierre Barbier de Reuille wrote:

> Well, for me, the more logical answer is : multi-inheritance !
> If part of your class is the same, (same semantic, same 
> implementation), then you want to have a base class for that.
>
> If you dislike this kindof inheritance, then your function should be 
> an external one. Even more because it's 'just' an implementation 
> function. The user don't need it as a method ... So why bother add it 
> to your object ?
>
> Pierre
>
> Xif a יcrit :
>
>> Javier Ruere wrote:
>>
>>> Xif wrote:
>>>
>>>> Hello
>>>>
>>>> There are several different objects. However, they all share the same
>>>> function.
>>>>
>>>> Since they are not the same or similar, it's not logical to use a
>>>> common superclass.
>>>>
>>>> So I'm asking, what's a good way to allow those objects to share that
>>>> function?
>>>>
>>>> The best solution I've found so far is to put that function in a
>>>> module, and have all objects import and use it. But I doubt that's a
>>>> good use-case for modules; writing and importing a module that 
>>>> contains
>>>> just a single function seems like an abuse.
>>>>
>>>> Thanks,
>>>> Xif
>>>
>>>
>>>
>>>
>>>   Could you give an example?
>>>
>>> Javier
>>>
>>> _______________________________________________
>>> Tutor maillist  -  Tutor at python.org
>>> http://mail.python.org/mailman/listinfo/tutor
>>>
>>> +++++++++++++++++++++++++++++++++++++++++++
>>> This Mail Was Scanned By Mail-seCure System
>>> at the Tel-Aviv University CC.
>>>
>> Sure, I can describe my particular case.
>>
>> It's a program that retrieves / updates Microsoft Excel spreadsheet 
>> data.
>>
>> There are two major classes:
>>
>> 1) an Excel class, that represents of the whole Excel program
>> 2) a Cells class, that abstracts retrieval  and editing of cells.
>>
>> Both classes use a function called getCells() as part of their 
>> __getitem__() methods.
>>
>> getCells() parses the __getitem__() call arguments, and returns an 
>> iterator over the appropriate cells.
>>
>> The difference between the 2 classes is that a Cells instance just 
>> converts the generator into a list and returns it:
>>
>> #<code>
>> return list(getCells(self.sheet, cells))
>> #</code>
>>
>> while an Excel instance returns the values of the cells:
>>
>> #<code>
>> return [cell.Value for cell in getCells(self.sheet, cells)]
>> #</code>
>>
>> As you can see, both use the getCells() function.
>>
>> So my question is, where is the best way to put it so instances of 
>> both classes can use it?
>>
>> Xif
>> _______________________________________________
>> Tutor maillist  -  Tutor at python.org
>> http://mail.python.org/mailman/listinfo/tutor
>>
>