colored glasses (was: idea: slices)

[Jecel Assumpcao Jr <jecel@lsi.usp.br>]

Charles Fiterman wrote:
> 
> Slices connects well with another idea which I call colored glasses.
> 
> Given colored glasses on an object your changes to the object go
> to the colored glasses. To you it looks like you have changed the
> object but to other viewers the object remains constant.
> 
> [more glasses examples]

While I understand the advantages of your idea, it feels
too "magic" for my taste. It goes in the exact opposite
direction of persistent objects where the saving of
state to secondary store is invisible. Most novices
have a hard time dealing with the open/save commands
so I doubt they would find colored glasses very easy
to grasp.

> This connects well to slices. A slice is a kind of colored glasses.
> Changes stop at the slice. They only go to the object at commit time.

That is one way to do it. Another is to automatically
commit every change and have a way to undo it for the
rare cases where you need it.

-- Jecel