Theory and Practice of Action Semantics

Abstract

Action Semantics is a framework for the formal description
of programming languages. Its main advantage over other frameworks
is pragmatic: action-semantic descriptions (ASDs) scale up smoothly to
realistic programming languages. This is due to the inherent extensibility
and modifiability of ASDs, ensuring that extensions and changes to
the described language require only proportionate changes in its description.
(In denotational or operational semantics, adding an unforeseen
construct to a language may require a reformulation of the entire description.)
After sketching the background for the development of action semantics,
we summarize the main ideas of the framework, and provide a simple
illustrative example of an ASD. We identify which features of ASDs
are crucial for good pragmatics. Then we explain the foundations of
action semantics, and survey recent advances in its theory and practical
applications. Finally, we assess the prospects for further development
and use of action semantics.
The action semantics framework was initially developed at the University
of Aarhus by the present author, in collaboration with David Watt
(University of Glasgow). Groups and individuals scattered around five
continents have since contributed to its theory and practice.