%T From Safe Concurrent Processes to Process\-Classes? PLUSSING New Code by ROLLING out and Compile? %A Øyvind Teig %E Alan G. Chalmers, Majid Mirmehdi, Henk Muller %B Communicating Process Architectures 2001 %X This article expands a concurrent language to support implementation inheritance by making block structures of the super process\-class pluggable, and to interface inheritance by making the language\[rs]s protocol inheritable. The parallel \[rs]object\-based\[rs] concurrent language occam 2 has been used as a catalyst for the concept, causing the language in fact to become (almost?) \[rs]object\-oriented\[rs] (OO). The result is white\-box reuse between a \[rs]process\-class\[rs] and its sub process\-class, and black\-box reuse seen from the client side. Since occam is aliasing free and considered a \[rs]safe\[rs] concurrent language, the expansion we discuss here keeps those properties \- somewhat unusual for an OO system. This new language should be well suited in safety critical systems, since it has inherited the static (compile\-time) and analysable properties from occam proper. Basically, two new keywords are defined: PLUSSING and ROLLING. The language feature suggestion is on sketch level only and therefore not complete, no BNF description exists and no compiler has been written.