1,052 research outputs found
A Case Study in Refactoring Functional Programs
Refactoring is the process of redesigning existing code without changing its functionality. Refactoring has recently come to prominence in the OO community. In this paper we explore the prospects for refactoring functional programs. Our paper centres on the case study of refactoring a 400 line Haskell program written by one of our students. The case study illustrates the type and variety of program manipulations involved in refactoring. Similarly to other program transformations, refactorings are based on program equivalences, and thus ultimately on language semantics. In the context of functional languages, refactorings can be based on existing theory and program analyses. However, the use of program transformations for program restructuring emphasises a different kind of transformation from the more traditional derivation or optimisation: characteristically, they often require wholesale changes to a collection of modules, and although they are best controlled by programmers, their application may require nontrivial semantic analyses. The paper also explores the background to refactoring, provides a taxonomy for describing refactorings and draws some conclusions about refactoring for functional programs
Structured Review of the Evidence for Effects of Code Duplication on Software Quality
This report presents the detailed steps and results of a structured review of code clone literature. The aim of the review is to investigate the evidence for the claim that code duplication has a negative effect on code changeability. This report contains only the details of the review for which there is not enough place to include them in the companion paper published at a conference (Hordijk, Ponisio et al. 2009 - Harmfulness of Code Duplication - A Structured Review of the Evidence)
Refactoring Functional Programs
Refactoring is the process of redesigning existing code without changing its functionality. Refactoring has recently come to prominence in the OO community. In this paper we explore the prospects for refactoring functional programs. Our paper centres on the case study of refactoring a 400 line Haskell program written by one of our students. The case study illustrates the type and variety of program manipulations involved in refactoring. Similarly to other program transformations, refactorings are based on program equivalences, and thus ultimately on language semantics. In the context of functional languages, refactorings can be based on existing theory and program analyses. However, the use of program transformations for program restructuring emphasises a different kind of transformation from the more traditional derivation or optimisation: characteristically, they often require wholesale changes to a collection of modules, and although they are best controlled by programmers, their application may require nontrivial semantic analyses. The paper also explores the background to refactoring, provides a taxonomy for describing refactorings and draws some conclusions about refactoring for functional programs
Towards sound refactoring in erlang
Erlang is an actor-based programming
language used extensively for building concurrent, reactive
systems that are highly available and suff er minimum
downtime. Such systems are often mission critical, making
system correctness vital. Refactoring is code restructuring
that improves the code but does not change
behaviour. While using automated refactoring tools is
less error-prone than performing refactorings manually,
automated refactoring tools still cannot guarantee that
the refactoring is correct, i.e., program behaviour is preserved.
This leads to lack of trust in automated refactoring
tools. We rst survey solutions to this problem
proposed in the literature. Erlang refactoring tools as
commonly use approximation techniques which do not
guarantee behaviour while some other works propose the
use of formal methodologies. In this work we aim to
develop a formal methodology for refactoring Erlang
code. We study behavioural preorders, with a special focus
on the testing preorder as it seems most suited to
our purpose.peer-reviewe
An Approach to Invariant-based Program Refactoring
Refactoring tools include checking of an object-oriented program for the
fulfillment of preconditions, for ensuring correctness. However, program invariants
â semantic information about classes and fields assumed valid during program execution
â are not considered by this precondition checking. As a result, applicability
of automated refactorings is constrained in these cases, as refactorings that would be
applicable considering the invariants get rejected, usually requiring manual changes.
In this paper, we describe initial work on the use of program invariants (declared as
code annotations) to increase applicability of automated refactoring. We propose an
approach that uses primitive program transformations that employ the invariant to
make the program syntactically amenable to the desired refactoring, before applying
the refactoring itself
Evaluation of Kermeta for Solving Graph-based Problems
Kermeta is a meta-language for specifying the structure and behavior of graphs of interconnected objects called models. In this paper,\ud
we show that Kermeta is relatively suitable for solving three graph-based\ud
problems. First, Kermeta allows the specification of generic model\ud
transformations such as refactorings that we apply to different metamodels\ud
including Ecore, Java, and Uml. Second, we demonstrate the extensibility\ud
of Kermeta to the formal language Alloy using an inter-language model\ud
transformation. Kermeta uses Alloy to generate recommendations for\ud
completing partially specified models. Third, we show that the Kermeta\ud
compiler achieves better execution time and memory performance compared\ud
to similar graph-based approaches using a common case study. The\ud
three solutions proposed for those graph-based problems and their\ud
evaluation with Kermeta according to the criteria of genericity,\ud
extensibility, and performance are the main contribution of the paper.\ud
Another contribution is the comparison of these solutions with those\ud
proposed by other graph-based tools
Collaborative Verification-Driven Engineering of Hybrid Systems
Hybrid systems with both discrete and continuous dynamics are an important
model for real-world cyber-physical systems. The key challenge is to ensure
their correct functioning w.r.t. safety requirements. Promising techniques to
ensure safety seem to be model-driven engineering to develop hybrid systems in
a well-defined and traceable manner, and formal verification to prove their
correctness. Their combination forms the vision of verification-driven
engineering. Often, hybrid systems are rather complex in that they require
expertise from many domains (e.g., robotics, control systems, computer science,
software engineering, and mechanical engineering). Moreover, despite the
remarkable progress in automating formal verification of hybrid systems, the
construction of proofs of complex systems often requires nontrivial human
guidance, since hybrid systems verification tools solve undecidable problems.
It is, thus, not uncommon for development and verification teams to consist of
many players with diverse expertise. This paper introduces a
verification-driven engineering toolset that extends our previous work on
hybrid and arithmetic verification with tools for (i) graphical (UML) and
textual modeling of hybrid systems, (ii) exchanging and comparing models and
proofs, and (iii) managing verification tasks. This toolset makes it easier to
tackle large-scale verification tasks
SPEEDY: An Eclipse-based IDE for invariant inference
SPEEDY is an Eclipse-based IDE for exploring techniques that assist users in
generating correct specifications, particularly including invariant inference
algorithms and tools. It integrates with several back-end tools that propose
invariants and will incorporate published algorithms for inferring object and
loop invariants. Though the architecture is language-neutral, current SPEEDY
targets C programs. Building and using SPEEDY has confirmed earlier experience
demonstrating the importance of showing and editing specifications in the IDEs
that developers customarily use, automating as much of the production and
checking of specifications as possible, and showing counterexample information
directly in the source code editing environment. As in previous work,
automation of specification checking is provided by back-end SMT solvers.
However, reducing the effort demanded of software developers using formal
methods also requires a GUI design that guides users in writing, reviewing, and
correcting specifications and automates specification inference.Comment: In Proceedings F-IDE 2014, arXiv:1404.578
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