[Moose-dev] Re: About instance variable metaclass

[Stéphane Ducasse]

I'm not convinced because it means as michele stating that we are losing
the possibility to build Smalltalk specific analysis and I want this  
possibility.
Else I do not see why I invest in support SharedVariable support.
I need that for pharo analysis.

>
> Hi Stef,
>
> I read your original mail, and I said that I think all the trouble is
> really not worth it, because in fact it would be better to just not
> split the classes in the first place.

now in moose we have nearly already implemented all the conventions I  
proposed
I imagine that I thought about that before or for the first Famix st  
plugging (read the new other email I sent).

> Your original question was about putting isClassScope and isShared
> regardless of merging/not merging, and the rationale was how not to
> break analyses.

Yes

> I know that since 2 years we can choose to merge or
> not and I like that, but now I say that we do not really gain anything
> by even considering not merging, because in fact you will break
> analyses in one way or another (for example, what should
> FAMIXClass>>instanceSide return?)

itself when merging
and class when not.

I will rephrase. This is not really not breaking analysis since you  
have to know what you are doing
but this is been consistent at the level we can and providing  
stability when we can.

I have to check but a metaclass method should have a classScope  
already and independently
to the fact that it is merged or not.

So at the end, next time I will check because we already have  
everything except the shared
and the problem of name conflict between instance variables and class  
instance variable.

> If we merge, then the variable problem because straightforward, as you
> know. Furthermore, if we merge we will also make Smalltalk fit the
> language independent paradigm of FAMIX.

but the price is too high if I cannot analyse Smalltalk code with  
moose then it is useless to me.

Stef

>
>
> Cheers,
> Doru
>
>
>
> On Nov 8, 2008, at 8:59 AM, Stéphane Ducasse wrote:
>
>> Guys
>>
>> Do you ever read my mails? I was never considering abandoning class
>> and metaclass separation.
>> Then I would not spend/lose my time to introduce support for
>> ClassVariable if I would only focus
>> on language independence.
>> A side note you can ask the importer to **merge or not** since two
>> years so what is the problem?
>> You can decide for your experience what you want to do. Now reread my
>> original question
>> to understand what I was proposing.
>>
>> Still you are not replying to my original question so I will do it  
>> the
>> way I want
>> but people should not complain that I did not try to have a  
>> discussion
>> on the topic.
>>
>> Stef
>>
>>
>> On Nov 8, 2008, at 8:30 AM, Michele Lanza wrote:
>>
>>> I understand where this is coming from (basically everybody
>>> [including
>>> myself] using Moose thinks that metaclasses are noise most of the
>>> time, and one of the first things you do, is to "remove" them from
>>> the
>>> model). However, if I think back to the possibly only major reverse
>>> engineering experience on a very large Smalltalk system (the
>>> MediaGenix system back in 2001) there we produced a couple of views
>>> only about the (dark) class side, one of the questions being "where
>>> have they gone meta in the system?".
>>>
>>> The language independence is a valid argument, but following this
>>> line
>>> of thought there you have the reason why Java interfaces are still
>>> being modeled as classes where one has to use a couple of methods
>>> (e.g., isClass, etc.) to establish what they actually are.
>>>
>>> Coming back to Smalltalk, it looks like one would be giving up on
>>> details that are there already, just for the sake of language
>>> independence. And yes, the views about the dark side could also be
>>> produced if the instance and class side are merged, it just takes a
>>> bit longer, and makes the creation/conception of such views less
>>> obvious.
>>>
>>> Cheers
>>>
>>> Michele
>>>
>>> On 8-Nov-08, at 12:32 AM, Tudor Girba wrote:
>>>
>>>> Hi,
>>>>
>>>> I think we should always merge the instance and class side. The
>>>> reason
>>>> is that I have never felt the need to have them separated in FAMIX,
>>>> because analyses are usually meant to be language independent.
>>>> Anyone
>>>> else actually had a different experience?
>>>>
>>>> Distinguishing between the types of methods and variables should be
>>>> just enough, and we can kind of do it from a language independent
>>>> point of view. I think that should be enough.
>>>>
>>>> Also, if you have the instance/class sides separated you will
>>>> certainly have different results for analyses than if you have them
>>>> merged, regardless of what you do with the variables.
>>>>
>>>> Cheers,
>>>> Doru
>>>>
>>>>
>>>> On Nov 7, 2008, at 9:00 PM, Michele Lanza wrote:
>>>>
>>>>> I'm not sure whether merging is the right way to go. One argument
>>>>> in
>>>>> favor is that otherwise one ends up having a model full of "empty"
>>>>> metaclasses, as the large majority of metaclasses do not implement
>>>>> any
>>>>> methods. Visually this results in a system complexity view with
>>>>> dual
>>>>> inheritance hierarchies. One argument against is that if a
>>>>> metaclass
>>>>> does implement methods, in the case of a merge, the metaclass
>>>>> methods
>>>>> would be mixed up with the "normal" methods (of course you would
>>>>> still
>>>>> be able to differentiate them within the model). Merging would  
>>>>> just
>>>>> be
>>>>> trying to make up one (of the very few) shortcoming(s) of
>>>>> Smalltalk's
>>>>> design. With respect to shared variables, that's another thing
>>>>> that I
>>>>> think is a bit overengineered..
>>>>>
>>>>> Cheers
>>>>>
>>>>> Michele
>>>>>
>>>>>
>>>>> On 7-Nov-08, at 8:42 PM, Alexandre Bergel wrote:
>>>>>
>>>>>>>> As far as I can see, an analysis may depend on whether you  
>>>>>>>> merge
>>>>>>>> classes and metaclasses.
>>>>>>>> It seems hard to imagine than any analysis should be depend on
>>>>>>>> whether
>>>>>>>> there is such a merging.
>>>>>>>
>>>>>>> you mean independent?
>>>>>>> If we have the same data represented the same way independently
>>>>>>> of
>>>>>>> merging
>>>>>>> we favor that an analysis code does have to have different cases
>>>>>>> based
>>>>>>> on merging
>>>>>>> or not?
>>>>>>
>>>>>> Maybe there is something I misunderstood. Merging classes and
>>>>>> metaclasses when importing means that one single class will
>>>>>> represent
>>>>>> both the class and its metaclass I guess.
>>>>>> This means that there will be twice less classes in a model. A
>>>>>> system
>>>>>> complexity view on a imported (using merging) smalltalk
>>>>>> application
>>>>>> will be different than the one with no merging.
>>>>>> No?
>>>>>>
>>>>>> Alexandre
>>>>>>
>>>>>>
>>>>>> -- 
>>>>>> _,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:
>>>>>> Alexandre Bergel  http://www.bergel.eu
>>>>>> ^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
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>>>> --
>>>> www.tudorgirba.com
>>>> www.tudorgirba.com/blog
>>>>
>>>> "Value is always contextual."
>>>>
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>
> --
> www.tudorgirba.com
> www.tudorgirba.com/blog
>
> "Being happy is a matter of choice."
>
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