[Pharo-project] Regarding SimpleMorphic

Fernando Olivero fernando.olivero at usi.ch
Mon Apr 4 14:24:20 CEST 2011


A nice paper on this topic,

On the Notion of Inheritance (1996)  by Antero Taivalsaari
http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.110.7221

Fernando

On Mon, Apr 4, 2011 at 2:01 PM, Igor Stasenko <siguctua at gmail.com> wrote:
> On 31 March 2011 22:03, Stéphane Ducasse <stephane.ducasse at inria.fr> wrote:
>>>>
>>>
>>> Stef,
>>>
>>> I'm sure you really miss last year, but we're entering the second quarter of 2011 ;-)
>>>
>>> []s
>>>
>>> Getting back to the technical part of your post, I also always tried to understand why in some cases we end up with this strange hierarchy
>>
>> people long time ago thought that inheritance = reuse.
>>
>
> It is strange, because i learned that inheritance is _specialization_.
>
> And i actually haven't took much care about subtleties of this, before
> i met smalltalk and start coding in it. It is in smalltalk, where it
> become apparent to me:
> - subclassing is not a way to "extend" a superclass, it is a way to
> specialize a superclass.
>
>
>>> (which you mock saying Car inherits from Wheel), specially if we take in account Smalltalk is a single inheritance language, so you have only a shot to specialize a given class.
>>>
>>> Maybe the folks that did it in the past were less used to composing than inheriting and the second way saves writing some new methods to avoid breaking the Demeter principle?
>>
>> I'm quite sure that LOD was not their concern.
>>>
>>> Perhaps understanding the "crucial incident" could lead us to better roadmap. . .
>>
>> No. We know design. We should just implement it.
>>
>> Stef
>>
>
>
>
> --
> Best regards,
> Igor Stasenko AKA sig.
>
>



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