Mechanisms for controlling evolution in persistent object systems

Persistent programming is concerned with the creation and manipulation of data with arbitrary lifetimes. A requirement of such systems is that the data (including programs) must be capable of evolving and that evolution should be within the control of the application's programmer. This paper discusses some recent developments in persistent programming that enable controlled evolution. The areas discussed are: the use of type systems, the use of reflection and a new style of programming, only available in persistent object systems, called hyper-programming