Computer Science Department
School of Computer Science, Carnegie Mellon University
Respectful Type Converters For Mutable Types
Jeannette M. Wing and John Ockerbloom
Submitted to Volume on Foundations of Component Based Systems,
In previous work we defined respects for immutable types A, B, and T; in this paper we extend our notion to handle conversions between mutable types. This extension is non-trivial since we need to consider an object's behavior as it varies over time. We present in detail two examples to illustrate our ideas: one for converting between PNG images and GIF images and another for converting between different kinds of bounded event queues. We also discuss in less detail other real-world applications, namely those inspired by our Typed Object Model (TOM) conversion service built at Carnegie Mellon and by the infamous Year 2000 (Y2K) problem.