TRANSFORMGEN - AUTOMATING THE MAINTENANCE OF STRUCTURE-ORIENTED ENVIRONMENTS

A serious problem for programs that use persistent data is that inform ation created and maintained by the program becomes invalid if the per sistent types used in the program are modified in a new release. Unfor tunately, there has been little systematic treatment of the problem; c urrent approaches are manual, ad hoc, and time consuming both for prog rammers and users. In this article we present a new approach. Focusing on the special case of managing abstract syntax trees in structure-or iented environments, we show how automatic transformers can be generat ed in terms of an implementor's changes to the grammar of these enviro nments.