Mixed Environment

[Dan Rozenfarb]

Hello,
I am Dan Rozenfarb from Argentina.
In my master thesis work I have implemented Self-like objects in Squeak with
the purpose of having an environment with class-based and class-less object
mixed.  It is supposed to allow exploratory and incremental programming,
letting you evolute from class-less objects towards a more (mature?)
arrangment with hierarchies of classes.
In writing the "related work" section I looked for others environments for
comparison purposes and found no one.
Do you know of any language/environment which combines those features?

I will really appreciate all the information you may share

Thanks