Traces (A cut at the “make isn’t generic” problem)

Abstract

Object-oriented techniques are a powerful tool for making a system end-programmer specializable. But, in cases where the system not only accepts objects as input, but also creates objects internally, specialization has been more difficult. This has been referred to as the “make isn’t generic problem.” We present a new object-oriented language concept, called traces, that we have used successfully to support specialization in cases that were previously cumbersome. The concept of traces makes a fundamental separation between two kinds of inheritance in object-oriented languages: inheritance of default implementation — an aspect of code sharing; and inheritance of specialization, a sometimes static, sometimes dynamic phenomena.