Composing Programming Languages by Combining Action-Semantics Modules

This article demonstrates a method for composing a programming language by combining action-semantics modules. Each module is defined separately, and then a new module is defined by either extending or combining existing modules. This method enables the language designer to gradually develop a language by selecting, extending and combining suitable language modules. The resulting modular structure is substantially different from that previously employed in action-semantic descriptions. We also discuss how to resolve the conflicts that may arise when combining modules, and indicate some advantages that action semantics has over other approaches in this respect.