Hi Jose:

congratulations to your ECOOP paper. You reference some of our work
and compare it to your work on shells. Here is additional information:

One version of context objects has been implemented in
Demeter/Java and has been used very successfully in industrial projects:

@INPROCEEDINGS{cse:preventive,
AUTHOR = "Karl J. Lieberherr and Doug Orleans",
TITLE = "Preventive Program Maintenance in {Demeter/Java} (Research
Demonstration)",
BOOKTITLE = "International Conference on Software Engineering",
YEAR = "1997",
ADDRESS = "Boston, MA",
PAGES = "604-605",
EDITOR = "",
PUBLISHER = "ACM Press"
}

http://www.ccs.neu.edu/home/lieber/Demeter-and-Java.html

This is the version where context objects are attached to a method
call  to change the behavior of a group of classes for a duration
of the method call only. In Demeter/Java, the method called does
a traversal.
We call those kinds of context objects visitor objects since they follow
the Visitor pattern.

In Demeter/Java, it is possible to attach several visitor objects to the same
method call. Indeed this feature is used very often in Demeter/Java.

-- Karl