>Can you explain what you understand by 'dereferencing'? From my (naive)
>point of view Lex's description was that of a proxy and I would think that
>you just have to catch the cases where the normal lookup does not work

Instance variable accesses would also have to do the indirection check. 
The Tektronix Smalltalk (OOPSLA '86 paper) did use indirect ions for some 
becomed objects. It actually used about 6 heuristics to keep from 
swapping pointers in all of memory (become the hard way). If the objects 
were the same size the contents were swapped for instance. Only index 
able objects were actually made indirect. The index able part of large 
objects could be indirect anyway since the very large ones were stored in 
a separate object space. This was a win since a common usage of become; 
was to grow an array.

Pat Caudill