Context-oriented programming in ContextL: State of the art. In LISP50: Celebrating the 50th Anniversary of Lisp (pp. 1–5

There is a wide range of scenarios where software systems have to be able to behave differently according to their context of use. In Context-oriented Programming (COP), programs can be partitioned into behavioral variations that can be freely activated and combined at runtime with well-defined scopes, such that the program behavior is affected depending on context. About four years ago, we have intro-duced our vision of Context-oriented Programming and have presented the programming language ContextL as an exten-sion to the Common Lisp Object System (CLOS), as our first language extension that explicitly realizes this vision. Since then, ContextL has been picked up by various devel-opers world-wide, is now in use in several software systems, and has been continuously improved to meet the demands of its users. For these reasons, ContextL can currently be regarded as the most mature realization of COP concepts. In this paper, we give an overview of the major ingredients of ContextL, describe the developments in ContextL of the last four years, and sketch some future work