On Sunday 24 February 2002 19:18, Alan Kay wrote:
>       Goldstein and Bobrow eventually found a very interesting way to
> implement these enriched objects: they used Smalltalk instances for
> each role/perspective. So a PIE object could be made from many
> Smalltalk objects.

I suppose they used a flat "perspective space", right? Some other 
proposals allow role inheritance, but that easily becomes a big mess.

How do you know which perspective to use at any given time? How do you 
switch between them?

Sorry about the questions, but there is essentially nothing online 
about PIE. I am trying (http://www.merlintec.com:8080/software/8) to 
come up with something similar.

-- Jecel