[Cuis] Scoping rules for shared variables ?

[Nicolas Cellier]

2015-07-21 21:13 GMT+02:00 Peter van Rooijen <peter at aba-instituut.nl>:

> Hi Juan, Hannes,
>
> since you asked: the other Smaltalks I have looked at (Dolphin, VA, VW,
> ST/X, VSE, IIRC) already do it as I want it to work
> (Squeak does it "wrong" so perhaps it's not really a Smalltalk
> implementation)
>
> This is about the lookup logic when we see a name that is not a local name
> (local to the block, method or object)
>
> To resolve it (i.e., determine if it is a valid reference to a shared
> variable), this is the order of searching for the name:
>
> 1 pool dictionaries declared in this class (from left to right I presume
> but I don't care so I haven't paid attention)
> 2 classPool (i.e. the class variables defined in this class)
> 3 classPools in superclass chain
> 4 globals
>
> The code in Squeak (and Cuis) does something recursive in the lookup logic
> when it should not, which is probably based on an incorrect understanding
> of the lookup rules. I have to admit that it is not easy to find how this
> should be done, I have studied the Blue Book and ANSI-98 Smalltalk standard
> (long long ago) and they were a bit fuzzy. But the logic all the other
> dialects have also makes the most sense (to me) and works for some "clever"
> stuff I do to make code 100% portable between dialects, so that's how I
> like it to work.
>
>
Ah, you probably mean that you would not want the superclass pool
dictionaries to be inherited, right?

Nicolas


> Cheers, Peter
>
> BTW Hannes, I'm not sure I would be able to change this in Dolphin, but in
> the other dialects, probably. But like I said, there is no need, it is
> Squeak (and Cuis) that's the odd one out.
>
> On Tue, Jul 21, 2015 at 3:36 AM, Juan Vuletich <juan at jvuletich.org> wrote:
>
>> On 7/19/2015 6:01 PM, H. Hirzel wrote:
>>
>>> On 7/19/15, Peter van Rooijen<peter at aba-instituut.nl>  wrote:
>>> ....
>>>   I
>>>
>>>> recently changed the scoping rules for shared variables (I think they're
>>>> done wrong in the base image). I could change what I wanted easily. So I
>>>> think I am not in some outsider author group. Instead I am happy that I
>>>> could change what I wanted without needing anyone's approval or
>>>> cooperation.
>>>>
>>>
>> Great!
>>
>>  A note:
>>> This applies to any version / distribution of Smalltalk. But it means
>>> that you have your own version of the core system.
>>>
>>> Could you elaborate on the issue of the shared variables, maybe it is
>>> something to include in the core Cuis image?
>>>
>>> --Hannes
>>>
>>
>> Agree. It would be nice to know.
>>
>> Cheers,
>> Juan Vuletich
>>
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>
>
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