Re: [Pharo-users] How to intercept instvar write - MetaLinks + anonymous subclass problem

[Petr Fischer via Pharo-users]

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> is possible to intercept (before writeú all instance variable writes on every 
> existing objects?
> 
> I found a discussion here:
> http://forum.world.st/Is-it-possible-to-follow-an-object-through-a-computation-td5092459.html
> 
> Known solutions:
> ....
> 3) Metalinks - it's based on intercepting method calls, right? But I need to 
> intercept direct instance variable write, so probably not possible

Ok, I learned more about MetaLinks and it's perfectly possible to intercept 
instance variable writes via. installing MetaLink into object instance (cool) - 
then I can intercept instvar write, but one problem immediately occurs:
when installing MetaLink into object instance, an original object class is 
exchanged to anonymous subclass of the original class - and because typical #= 
method is implemented like:

=
        self == anObject
                ifTrue: [ ^ true ].
        self class = anObject class
                ifFalse: [ ^ false ].
        ...

then most of #= comparisons in application logic is broken due to "self class = 
anObject class" part.

Is there any way to solve this problem?

Thanks! pf

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