[self-interest] mirrors (second try)

[David P Harris]

Reinout Heeck wrote:

>Jecel Assumpcao Jr wrote:
>  
>
>>[...] the idea of using
>>different viewpoints instead of mirrors as suggested for Us.
>>
>>    
>>
>
>This sounds like something I need to know/understand but I completely fail to 
>comprehend what it references. What is meant by 'viewpoints' and 'Us', are we 
>talking about a design pattern here?
>  
>
Yes, Jecel, you need to reference these things better because some of us 
do not follow everything in detail.  I feel out of the loop and must be 
missing some other forum. 

I think Us refers to an other object-based language -- on off shoot of 
self.  I think it might be a Jecel language. 

Viewpoints, as I understand it, refers to having different views of the 
same object.  A common example would be a point.  You could have 
different different views: Cartesian and Radial.  They would refer to 
the same point, but have different interfaces and messages.  This is 
useful if you want to hide some of an object, say with a bank account, 
you might want a view that only showed the balance, but other views that 
could deposit or withdraw money.  Then permission would apply to the 
view and not the object, per se.

I have never understood mirrors however, as everyone assumes you know 
what they are.....so if someone can inform me as to what they are and 
why they are so darn useful ;-)

David