Context-oriented programming

Abstract

Context-dependent behavior is becoming increasingly important for a wide range of application domains, from pervasive computing to common business applications. Unfortunately, mainstream programming languages do not provide mechanisms that enable software entities to adapt their behavior dynamically to the current execution context. This leads developers to adopt convoluted designs to achieve the necessary runtime flexibility. We propose a new programming technique called Context-oriented Programming (COP) which addresses this problem. COP treats context explicitly, and provides mechanisms to dynamically adapt behavior in reaction to changes in context, even after system deployment at runtime. In this paper, we lay the foundations of COP, show how dynamic layer activation enables multi-dimensional dispatch, illustrate the application of COP by examples in several language extensions, and demonstrate that COP is largely independent of other commitments to programming style.

A comparison of context-oriented programming languages

“…ContextL provides several special features that are presented in Section 3. Subsequently, several meta-level libraries for dynamic pro- gramming languages were developed, namely ContextS [9] for Smalltalk, ContextR [15] for Ruby, ContextJS for JavaScript, ContextPy [16] and PyContext [17] for Python, and ContextG for Groovy. Aside from these dynamic languages, three COP extensions to the Java programming language exist, namely ContextJ [1], ContextJ* [10], and ContextLogicAJ [2].…”

“…PyContext [17] suggests the concepts of dynamic variables [7] and implicit layer activation. Dynamic variables allow developers to access contextual state without additional pass-through parameters in the method signature.…”

Decisions: Algebra and Implementation

“…Andersson et al compose and optimize special implementations of data structures and algorithms, considering matrix multiplication as a case study [2]. This work may be considered as a generalization of the dispatch mechanism in object-oriented languages, for instance in the sense of Context-Oriented Programming (COP) [76,27,14].…”

Improving the development of context-dependent Java applications with ContextJ

“…Several COP extensions have been developed for dynamic programming languages such as Lisp [5], Smalltalk [7], Python [14,15], and Ruby [13]. They have been implemented using the respective language's meta-level facilities; none of them utilizes bytecode transformation as done in ContextJ.…”

“…A layer can be dynamically activated and composed with other layers, allowing fine-grained control of an application's runtime behavior. COP has been implemented as extension to several programming languages [5,7,[13][14][15] to support various problem domains.…”