Functional programming languages for verification tools: experiences with ML and Haskell

We compare Haskell with ML as programming languages for verification tools, based on our experience developing TRUTH in Haskell and the Edinburgh Concurrency Workbench (CWB) in ML. We discuss not only technical language features but also the "worlds" of the languages, for example, the availability of tools and libraries

Resource Usage Protocols for Iterators

We discuss usage protocols for iterator objects that prevent concurrent modifications of the underlying collection while iterators are in progress. We formalize these protocols in Java-like object interfaces, enriched with separation logic contracts. We present examples of iterator clients and proofs that they adhere to the iterator protocol, as well as examples of iterator implementations and proofs that they implement the iterator interface

Session Types with Runtime Adaptation: Overview and Examples

In recent work, we have developed a session types discipline for a calculus that features the usual constructs for session establishment and communication, but also two novel constructs that enable communicating processes to be stopped, duplicated, or discarded at runtime. The aim is to understand whether known techniques for the static analysis of structured communications scale up to the challenging context of context-aware, adaptable distributed systems, in which disciplined interaction and runtime adaptation are intertwined concerns. In this short note, we summarize the main features of our session-typed framework with runtime adaptation, and recall its basic correctness properties. We illustrate our framework by means of examples. In particular, we present a session representation of supervision trees, a mechanism for enforcing fault-tolerant applications in the Erlang language.Comment: In Proceedings PLACES 2013, arXiv:1312.221

CaSPiS: A Calculus of Sessions, Pipelines and Services

Service-oriented computing is calling for novel computational models and languages with well disciplined primitives for client-server interaction, structured orchestration and unexpected events handling. We present CaSPiS, a process calculus where the conceptual abstractions of sessioning and pipelining play a central role for modelling service-oriented systems. CaSPiS sessions are two-sided, uniquely named and can be nested. CaSPiS pipelines permit orchestrating the flow of data produced by different sessions. The calculus is also equipped with operators for handling (unexpected) termination of the partner’s side of a session. Several examples are presented to provide evidence of the flexibility of the chosen set of primitives. One key contribution is a fully abstract encoding of Misra et al.’s orchestration language Orc. Another main result shows that in CaSPiS it is possible to program a “graceful termination” of nested sessions, which guarantees that no session is forced to hang forever after the loss of its partner

Koka: Programming with Row Polymorphic Effect Types

We propose a programming model where effects are treated in a disciplined way, and where the potential side-effects of a function are apparent in its type signature. The type and effect of expressions can also be inferred automatically, and we describe a polymorphic type inference system based on Hindley-Milner style inference. A novel feature is that we support polymorphic effects through row-polymorphism using duplicate labels. Moreover, we show that our effects are not just syntactic labels but have a deep semantic connection to the program. For example, if an expression can be typed without an exn effect, then it will never throw an unhandled exception. Similar to Haskell's `runST` we show how we can safely encapsulate stateful operations. Through the state effect, we can also safely combine state with let-polymorphism without needing either imperative type variables or a syntactic value restriction. Finally, our system is implemented fully in a new language called Koka and has been used successfully on various small to medium-sized sample programs ranging from a Markdown processor to a tier-splitted chat application. You can try out Koka live at www.rise4fun.com/koka/tutorial.Comment: In Proceedings MSFP 2014, arXiv:1406.153

Development of a Secured Information System to Manage Malaria Related Cases in South Western region of Nigeria

Effective community based management of malaria incidences in most community health care centers are hampered by failure in the prompt diagnosis and treatment of malaria. This challenge is exacerbated by the emergence of multidrug resistant plasmodium parasites which makes ineffective most of the effective therapeutic drugs used in the treatment of malaria. Furthermore, even at abrupt changes in the therapeutic recommendations does not always translate to an immediate change in the effective management and control of malaria. Thus, the quest for effective diagnosis and appropriate treatment becomes a daunting and necessary task. . In this article, a secured Information system to manage malaria related cases was developed by 2-tier architecture by using the VB.NET programming language within the Microsoft Visual studio 2008 edition. The database employed for storing relevant data was the SQL server 2005 edition and fingerprint device integrated into the information system was the Microsoft fingerprint reader. From the results in this study, we modeled a feasible medical history system for prompt diagnosis, effective drug recommendations and promulgation of policies that would serve as palliatives for community health care centers that suffers shortages in material and human resources handling malaria and its related diseases

Two Decades of Maude

This paper is a tribute to José Meseguer, from the rest of us in the Maude team, reviewing the past, the present, and the future of the language and system with which we have been working for around two decades under his leadership. After reviewing the origins and the language's main features, we present the latest additions to the language and some features currently under development. This paper is not an introduction to Maude, and some familiarity with it and with rewriting logic are indeed assumed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech