Program Execution Environments as Contextual Values

Context-oriented programming (COP) provides a very intuitive way to handle run-time behavior varying in several dimensions. However, COP usually requires major language extensions and implies a considerable performance loss. To avoid language extensions we propose to specify program execution environments as contextual values in separate units. A tool translates such specifications into C++ classes usable in the rest of the program. Without the need of multiple dispatch, the performance can largely profit from simple caching. Furthermore, it is easy to support debugging and store contextual values in configuration files.