[Cuis-dev] Tweaks for PreferenceNG

[Hilaire Fernandes]

I changed the subject.

Le 14/05/2022 à 17:49, Juan Vuletich a écrit :
>
> I think that #initialize should discard everything and start anew.

I was lazy to tackle the problem now as it will make the class more complex.

> Please review the attach. It creates a new dictionary, populates it, 
> and only then installs it as the new ThePreferences. This is a pattern 
> that has been used in Squeak/Cuis many times.

I don't really like much, it makes the class very verbose and harder to 
understand, added redirections, but I don't have clear workaround now. 
Analyzing now...
I am wondering: could it be possible to put Cuis in hold while 
initializing, it will avoid race condition, and kept the class simple, 
hum not really fancy, no idea of the implication of a such approach.
Another idea is to use two class variables PreferenceReadAccess and 
PreferenceWriteAccess. In normal operation the two reference the same 
Dictionary. During initialization, they are decoupled and 
PreferenceWriteAccess is set to a new empty dictionary. #at: and 
#at:put: will be rewritten accordingly to use these variables.

It will keep the class simpler. I think I like this approach.

What do you think? If you agree I can make write the code.

Other observations:

The class method #name:description:category:type:value: is needed, with 
it the user describes completely a new preference. It is needed by 
external packages introducing their own preferences. For example in the 
Locale package I have been porting a few weeks ago there is:

Locale class>>initialize
     Smalltalk addToStartUpList: Locale.
     PreferenceNG
         name: #useLocale
         description: 'Use the system locale to set the system language, 
etc., at startup.  For time-zone handling, see automaticTimezone.'
         category: #system
         type: Boolean
         value: false

The instance creation method #name:category:value is a shorter/lazy one, 
where the system can deduce the type and no description is provided. If 
one instance creation should be removed it could be this one.


>
> BTW, I removed #select:, and renamed #all to #allPreferences. I think 
> this makes the stuff easier to find with 

#select: is needed for a preference browser. Applications introducing a 
new category of preferences (think #drgeo category for example) may want 
to use this selector too. I think it should be reintroduced (with a 
better name?) it will avoid to get it reintroduced in several 
application package.

Good point on #all!

Thanks

Hilaire

-- 
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http://drgeo.eu
http://blog.drgeo.eu
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