[Pharo-dev] Losing instance variable addition

Esteban Lorenzano estebanlm at gmail.com
Thu Oct 31 07:23:52 EDT 2013


I'm with Doru here, we already have the capability of extend completely the system (not just to extend methods). Even if can be dangerous, that's a choice of the user. 
Our tools should empower the features of the language, not restrict them.


On Oct 31, 2013, at 7:49 AM, Camillo Bruni <camillobruni at gmail.com> wrote:

> 
> On 2013-10-31, at 09:55, Clément Bera <bera.clement at gmail.com> wrote:
> 
>> Basically here we discuss how to introduce in Pharo stateful class extension and stateful traits. I like these features a lot because it means I would be able to reuse the same class differently depending on the context and the surrounding classes. But if we overuse that we will definitely go into chaos. Martin tried in Mist and he concluded that he should have class composition instead of stateful traits / class extension. 
> 
> right, using stateful traits a quite a bit different than directly adding inst vars ;). 
> This way you can easily ensure that the added variable is only visible to the new code and hence you do not run into the override limbo. Now that we have first-class slots, doing these things gets much easier (note that stateful traits was an example implementation in the slot paper).
> 
> I think the resulting "mess", which we already have with normal traits, is the lack of tools. For instances, pharo didn't properly respect traits in the IDE for years with the result that most of the trait methods slowly vanished.





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