James F. Power’s research while affiliated with National University of Ireland, Maynooth and other places

This “journal-first” paper summarises a publication by the same authors in the journal Logical Methods in Computer Science which describes a formal semantics for the Event-B specification language using the theory of institutions. It defines an institution for Event-B and shows how the constructs of the Event-B specification language can be mapped into our institution. This algebraic semantics distinguishes three constituent sub-languages of Event-B: the superstructure, infrastructure and mathematical languages. An important impact of this work is that our semantics provides access to the generic modularisation constructs available in institutions, including specification-building operators for parameterisation and refinement. We demonstrate how these features subsume and enhance the corresponding features already present in Event-B through a detailed study of their use in a worked example. Further benefits of the institutional approach are its provision for mathematically definable interoperability to facilitate heterogeneous specification.KeywordsEvent-BSemanticsModularisationInteroperability

This paper describes a formal semantics for the Event-B specification language using the theory of institutions. We define an institution for Event-B, EVT, and prove that it meets the validity requirements for satisfaction preservation and model amalgamation. We also present a series of functions that show how the constructs of the Event-B specification language can be mapped into our institution. Our semantics sheds new light on the structure of the Event-B language, allowing us to clearly delineate three constituent sub-languages: the superstructure, infrastructure and mathematical languages. One of the principal goals of our semantics is to provide access to the generic modularisation constructs available in institutions, including specification-building operators for parameterisation and refinement. We demonstrate how these features subsume and enhance the corresponding features already present in Event-B through a detailed study of their use in a worked example. We have implemented our approach via a parser and translator for Event-B specifications, EBtoEVT, which also provides a gateway to the Hets toolkit for heterogeneous specification.

This paper describes a formal semantics for the Event-B specification language using the theory of institutions. We define an institution for Event-B, EVT, and prove that it meets the validity requirements for satisfaction preservation and model amalgamation. We also present a series of functions that show how the constructs of the Event-B specification language can be mapped into our institution. Our semantics sheds new light on the structure of the Event-B language, allowing us to clearly delineate three constituent sub-languages: the superstructure, infrastructure and mathematical languages. One of the principal goals of our semantics is to provide access to the generic modularisation constructs available in institutions, including specification-building operators for parameterisation and refinement. We demonstrate how these features subsume and enhance the corresponding features already present in Event-B through a detailed study of their use in a worked example. We have implemented our approach via a parser and translator for Event-B specifications, EBtoEVT, which also provides a gateway to the Hets toolkit for heterogeneous specification.

This paper presents an experience report from a third-year undergraduate compiler design course that is taught as part of a four year computer science degree. We analyse data from a study of practical assignments, evaluated in the context of take-home formative assignments and a supervised summative examination. We implement metrics to quantify the degrees of similarity between submissions for programming assignments, as well as measuring the level of activity. We present the results of our study, and discuss the utility of these metrics for our teaching practice.

Python is one of the most popular and widely adopted programming languages in use today. In 2008 the Python developers introduced a new version of the language, Python 3.0, that was not backward compatible with Python 2, initiating a transitional phase for Python software developers. In this paper, we describe a study that investigates the degree to which Python software developers are making the transition from Python 2 to Python 3. We have developed a Python compliance analyser, PyComply, and have analysed a previously studied corpus of Python applications called Qualitas. We use PyComply to measure and quantify the degree to which Python 3 features are being used, as well as the rate and context of their adoption in the Qualitas corpus. Our results indicate that Python software developers are not exploiting the new features and advantages of Python 3, but rather are choosing to retain backward compatibility with Python 2. Moreover, Python developers are confining themselves to a language subset, governed by the diminishing intersection of Python 2, which is not under development, and Python 3, which is under development with new features being introduced as the language continues to evolve. © 2018 Springer Science+Business Media, LLC, part of Springer Nature

In this paper, we describe our experience in grammar engineering to construct multiple parsers and front ends for the Python language. We present a metrics‐based study of the evolution of the Python grammars through the multiple versions of the language in an effort to distinguish and measure grammar evolution and to provide a basis of comparison with related research in grammar engineering. To conduct this research, we have built a toolkit, pygrat, which builds on tools developed in other research. We use pygrat to build a system that automates much of the process needed to translate the Python grammars from EBNF to a formalism acceptable to the bison parser generator. We exploit the suite of Python test cases, used by the Python developers, to validate our parser generation. Finally, we describe our use of the menhir parser generator to facilitate the parser and front‐end construction, eliminating some of the transformations and providing practical support for grammar modularisation.

Model-driven engineering is an effective approach for addressing the full life cycle of software development. Model transformation is widely acknowledged as one of its central ingredients. With the increasing complexity of model transformations, it is urgent to develop verification tools that prevent incorrect transformations from generating faulty models. However, the development of sound verification tools is a non-trivial task, due to unimplementable or erroneous execution semantics encoded for the target model transformation language. In this work, we develop a formalisation for the EMFTVM bytecode language by using the Boogie intermediate verification language. It ensures the model transformation language has an implementable execution semantics by reliably prototyping the implementation of the model transformation language. It also ensures the absence of erroneous execution semantics encoded for the target model transformation language by using a translation validation approach.

This paper presents a formalisation of the Event-B formal specification language in terms of the theory of institutions. The main objective of this paper is to provide: (1) a mathematically sound semantics and (2) modularisation constructs for Event-B using the specification-building operations of the theory of institutions. Many formalisms have been improved in this way and our aim is thus to define an appropriate institution for Event-B, which we call $\mathcal {EVT}$. We provide a definition of $\mathcal {EVT}$ and the proof of its satisfaction condition. A motivating example of a traffic-light simulation is presented to illustrate our approach.