Monads are a mechanism for embedding and reasoning about notions of computation such as mutable state, I/O, exceptions, and many others. Even though monads are technically language-agnostic, they are mostly associated with the Haskell language. Indeed, one could argue that the use of monads is one of the defining characteristic of the Haskell language. In practical terms, monadic programming in Haskell

Replication can be used to increase the availability of a service by creating many operational copies of its data called replicas. Active replication is a form of replication that has strong consistency semantics, which are easier to reason about and program. However, creating replicated services using active replication still demands from the programmer the knowledge of subtleties of the replication

A large dataset that contains the eye movements of N=216 programmers of different experience levels captured during two code comprehension tasks is presented. Data are grouped in terms of programming expertise (from none to high) and other demographic descriptors. Data were collected through an international collaborative effort that involved eleven research teams across eight countries on four continents

This paper presents BoundWarden, a novel spatial memory safety enforcement approach that utilizes a combination of compile-time transformation and runtime concurrent monitoring techniques. The compiler extension component of BoundWarden transparently instruments source code of C programs with the code that allows the runtime component of BoundWarden to comprehensively detect and prevent buffer overflow

Community Question and Answer (CQA) platforms use the power of online groups to solve problems, or gain information. While these websites host useful information, it is critical that the details provided on these platforms are of high quality, and that users can trust the information. This is particularly necessary for software development, given the ubiquitous use of software across all sections of

In the domain of model-driven engineering, patterns have emerged as a ubiquitous structuring mechanism. Patterns are used for instance at the requirement analysis level, during system design, and during the deployment and code generation phases. We focus on formalizing the operational semantics of pattern application on component-based system designs. More precisely, our ultimate goal is to provide

The verification of contemporary distributed software systems is challenging, because they are heavily parameterised, containing components whose number and connections cannot be a priori fixed. In this work, we consider the multi-parameterised verification of safety properties by refinement checking in the context of labelled transition systems (LTSs). The LTSs are parameterised by using first-order

Complex Event Processing (CEP) is a powerful technology thoroughly used in cutting-edge software architectures to support decision-making in multiple domains. Currently, developing such CEP-enhanced software architectures is not an easy task and there are no general purpose Application Programming Interfaces (APIs) which support programming and software development for CEP-based systems. This paper

Use Case (UC) quality impacts the overall quality and defect rate of a system, as they specify the expected behavior of an implementation. In a previous work, we have defined an approach for a step-by-step translation from UCs written in natural language to a formal description in terms of Graph Transformation (GT), where each step of the UC was translated to a transformation rule. This UC formalization

The growing complexity and diversity of models used for engineering dependable systems implies that a variety of formal methods, across differing abstractions, paradigms, and presentations, must be integrated. Such an integration requires unified semantic foundations for the various notations, and co-ordination of a variety of automated verification tools. The contribution of this paper is Isabelle/UTP

Event-B is a formal method that utilizes a stepwise development approach for system-level modeling and analysis. We are interested in reasoning about real-time deadlines and delays between trigger and response events. There is existing work on treating these properties in Event-B but it lacks a semantic treatment in terms of trace behaviors. Because timing properties require fairness assumptions, we

Operational and denotational are two common approaches to specify the semantics of programming languages: the former is more suitable for expressing a particular evaluation strategy and the latter is more abstract. If there are both an operational and a denotational semantics for a programming language, one expects that the operational semantics be adequate with respect to the denotational one (this

The vast divide between the speed of CPU and RAM means that effective use of CPU caches is often a prerequisite for high performance on modern architectures. Hence, developers need to consider how to place data in memory so as to exploit spatial locality and achieve high memory bandwidth. Such manual memory optimisations are common in unmanaged languages (e.g. C, C++), but they sacrifice readability

Software requirement analysis can undoubtedly benefit from prevention and early detection of failures, in particular by some kind of automatic analysis. Formal methods offer means to represent and analyze requirements with rigorous tools, avoiding ambiguities, and allowing automatic verification of requirement consistency. However, formalisms often clash in the culture or lack of software analysts'

We provide a construction that, given a big-step semantics describing finite computations and their observations, extends it to include infinite computations as well. The basic idea is that the finite behavior uniquely determines the infinite behavior once observations and their composition operators are fixed. Technically, the construction relies on the framework of inference systems with corules

Gradual typing is an effective approach to integrate static and dynamic typing, which supports the smooth transition between both extremes via the imprecision of type annotations. Gradual typing has been applied in many scenarios such as objects, subtyping, effects, ownership, typestates, information-flow typing, parametric polymorphism, etc. In particular, the combination of gradual typing and mutable

This paper presents CHOReVOLUTION, a platform for the tool-assisted realization and execution of distributed applications. CHOReVOLUTION specifically targets service-oriented systems specified through service choreographies. It offers an Integrated Development and Runtime Environment (IDRE) organized into three layers, namely, front-end, back-end, and cloud. It comprises a wizard-aided development

The RPC calculus is a simple semantic foundation for multi-tier programming languages such as Links in which located functions can be written for the client-server model. Subsequently, the typed RPC calculus is designed to capture the location information of functions by types and to drive location type-directed slicing compilations. However, the use of locations is currently limited to monomorphic

Deadlock and nondeterminism may become increasingly hard to detect in concurrent and distributed systems. UML activity diagrams are flowcharts that model sequential and concurrent behavior. Although the UML community widely adopts such diagrams, there is no standard approach to verify the presence of deadlock and nondeterministic behavior in activity diagrams. Nondeterminism is usually neglected in

Most current programming languages do not restrict the use of the concurrency primitives they provide, leaving it to the programmer to detect data races. In this paper, we revisit the monitor model, which guards against data races by guaranteeing that accesses to shared variables occur only inside monitors, and show that this concept can be implemented in a programming language with referential semantics

Property-based testing of compilers or programming language semantics is difficult to accomplish because it is hard to design a random generator for valid programs. Most compiler test tools do not have a well-specified way for generating type-correct programs, which is a requirement for such testing activities. In this project, we formalize a type-directed procedure to generate random well-typed Java

Compositional model checking approaches attempt to limit state space explosion by iteratively combining the behaviour of the components in a concurrent system and reducing the result modulo an appropriate equivalence relation. In this article, we consider Labelled Transition Systems (LTSs), in which transitions are labelled by actions, to describe component behaviour, and LTS networks to combine the

Source code metrics extraction is a complex task that has to be done automatically given the current size of software. They are extracted using software metric tools and more generic extraction mechanisms. These mechanisms usually work by querying a source code representation model. These models are static, and the information that can be obtained from them is limited. In this work an extraction methodology

The present work describes a challenging, real-life finalization scenario that applies combined scalability and resource utilization pressure. Neither weak reference arrays nor ephemerons satisfactorily address the performance-critical demands, hence addressing these existing limitations requires a new strategy. This paper puts forward a hybrid weak arrayed container with properties from both weak

Redundancy concepts are major design drivers in fault-tolerant space systems. It can be a difficult task to decide when to activate which redundancy, and which component should be replaced. In this paper, we refine a methodology where recovery strategies are synthesized from a model of non-deterministic dynamic fault trees. The synthesis is performed by transforming non-deterministic dynamic fault

The design of complex systems involves several design models supporting different analysis techniques for validation and verification purposes. These activities lead to the definition of heterogeneous modelling languages and analysis techniques. In this setting, meeting certification standards becomes a key issue in system engineering. Reducing heterogeneity due to the presence of different modelling

Streaming APIs are becoming more pervasive in mainstream Object-Oriented programming languages and platforms. For example, the Stream API introduced in Java 8 allows for functional-like, MapReduce-style operations in processing both finite, e.g., collections, and infinite data structures. However, using this API efficiently involves subtle considerations such as determining when it is best for stream

Context: Most modern programming environments support refactorings. Although refactorings are relevant to improve the quality of software source code, they unfortunately suffer from severe usability issues. In particular, the extract method refactoring, one of the most prominent refactorings, has a failure rate of 49% when users attempt to use it. Objective: Our main objective is to improve the success

The term traits is overloaded in the literature. In this work we refer to traits as the stateless model and implementation described in Schaerli et al. articles. Traits provide a flexible way to support multiple inheritance code reuse in the context of a single inheritance language. The Pharo programming language includes the second implementation of stateless traits based on the original version of

Rewriting is a framework for reasoning about functional programming. The dependency pair criterion is a well-known mechanism to analyze termination of term rewriting systems. Functional specifications with an operational semantics based on evaluation are related, in the rewriting framework, to the innermost reduction relation. This paper presents a PVS formalization of the dependency pair criterion

Data races are often discussed in the context of lock acquisition and release, with race-detection algorithms routinely relying on vector clocks as a means of capturing the relative ordering of events from different threads. In this paper, we present a data-race detector for a language with channel communication as its sole synchronization primitive, and provide a semantics directly tied to the happens-before

Context and motivation All the research in methods and tools for avoiding, detecting, and removing ambiguities in requirements specifications assumes that doing so is necessary and that the methods and tools for doing so are worth the effort to use them. Each of two attempts by de Bruijn et al and Philippo et al to test these assumptions empirically with a case study examined a random sampling of the

We present a formalization of bounded grids using Lean proof assistant and provide a formalized implementation along with an interface consisting of various definitions together with their proven–correct properties serving to manipulate grids in general fashion regardless of the intended use case. We then proceed to demonstrate the applicability of the grids by interpreting them as matrices, followed

Recent advances in machine learning and artificial intelligence are now being considered in safety-critical autonomous systems where software defects may cause severe harm to humans and the environment. Design organizations in these domains are currently unable to provide convincing arguments that their systems are safe to operate when machine learning algorithms are used to implement their software

One of the leading textbooks for formal methods is Software Foundations (SF), written by Benjamin Pierce in collaboration with others, and based on Coq. After five years using SF in the classroom, we came to the conclusion that Coq is not the best vehicle for this purpose, as too much of the course needs to focus on learning tactics for proof derivation, to the cost of learning programming language

Many frameworks exist for programmers to develop and deploy Big Data applications such as Hadoop Map/Reduce and Apache Spark. However, very little debugging support is currently provided in those frameworks. When an error occurs, developers are lost in trying to understand what has happened from the information provided in log files. Recently, new solutions allow developers to record & replay the application

We compare different algorithms for computing eigenvalues and eigenvectors of a symmetric band matrix across a wide range of synthetic test problems. Of particular interest is a comparison of state-of-the-art tridiagonalization-based methods as implemented in Lapack or Plasma on the one hand, and the block divide-and-conquer (BD&C) algorithm as well as the block twisted factorization (BTF) method on