Contextual values

ABSTRACT

Context-oriented programming proposes to treat execution context explicitly and to provide means for context-dependent adaptation at runtime. There are many mechanisms that can be used to make either variable bindings or application code adapt dynamically, like dynamically-scoped variables, dynamic layer activation, and contextual dispatch. There are no means however, to make actual values be context-dependent. This means that side effects engendered by dynamically-activated adaptations are potentially global. We propose contextual values: values that actually depend on the context in which they are looked at and modified. We explore how contextual values can be provided, either as a simple library or directly into the language through different designs, for which we provide the operational semantics in the form of Scheme interpreters. Being able to scope side effects to certain contexts is a step forward for context-oriented programming, and can have interesting applications in other areas like security and dynamic software evolution.

REFERENCES

• 1: M. Baldauf and S. Dustdar. A survey on context-aware systems. Technical Report TUV-1841-2004-24, Technical University of Vienna, 2004.
• 2: Alexandre Bergel , Stéphane Ducasse , Oscar Nierstrasz, Classbox/J: controlling the scope of change in Java, Proceedings of the 20th annual ACM SIGPLAN conference on Object oriented programming, systems, languages, and applications, October 16-20, 2005, San Diego, CA, USA
• 3: Licia Capra , Wolfgang Emmerich , Cecilia Mascolo, Reflective Middleware Solutions for Context-Aware Applications, Proceedings of the Third International Conference on Metalevel Architectures and Separation of Crosscutting Concerns, p.126-133, September 25-28, 2001
• 4: Keith Cheverst, Christos Efstratiou, Nigel Davies, and Adrian Friday. Architectural ideas for the support of adaptive context-aware applications. In Workshop on Infrastructure for Smart Devices - How to Make Ubiquity an Actuality, Bristol, UK, September 2000.
• 5: Curtis Clifton , Gary T. Leavens , Craig Chambers , Todd Millstein, MultiJava: modular open classes and symmetric multiple dispatch for Java, Proceedings of the 15th ACM SIGPLAN conference on Object-oriented programming, systems, languages, and applications, p.130-145, October 2000, Minneapolis, Minnesota, United States
• 6: Pascal Costanza. How to make Lisp more special. In Proceedings of International Lisp Conference, Stanford, CA, USA, June 2005.
• 7: Pascal Costanza , Robert Hirschfeld, Language constructs for context-oriented programming: an overview of ContextL, Proceedings of the 2005 symposium on Dynamic languages, p.1-10, October 18-18, 2005, San Diego, California [doi>10.1145/1146841.1146842]
• 8: David R. Morse , Stephen Armstrong , Anind K. Dey, The what, who, where, when, why and how of context-awareness, CHI '00 extended abstracts on Human factors in computing systems, April 01-06, 2000, The Hague, The Netherlands [doi>10.1145/633292.633518]
• 9: Christopher Dutchyn , David B. Tucker , Shriram Krishnamurthi, Semantics and scoping of aspects in higher-order languages, Science of Computer Programming, v.63 n.3, p.207-239, 15 December 2006 [doi>10.1016/j.scico.2006.01.003]
• 10: Matthew Flatt. PLT MzScheme: Language manual, 2007. Version 372.
• 11: Daniel P. Friedman , Christopher T. Haynes , Mitchell Wand, Essentials of programming languages (2nd ed.), Massachusetts Institute of Technology, Cambridge, MA, 2001
• 12: Martin Gasbichler and Michael Sperber. Processes vs. user-level threads in scsh. In 3rd Workshop on Scheme and Functional Programming, October 2002.
• 13: Sebastián González , Kim Mens , Patrick Heymans, Highly dynamic behaviour adaptability through prototypes with subjective multimethods, Proceedings of the 2007 symposium on Dynamic languages, October 22-22, 2007, Montreal, Quebec, Canada [doi>10.1145/1297081.1297094]
• 14: J. Kephart. A vision of autonomic computing. In Onward! Track at OOPSLA 2002, pages 13-36, Seattle, WA, USA, 2002.
• 15: Richard A. Kelsey , Jonathan A. Rees, A tractable Scheme implementation, Lisp and Symbolic Computation, v.7 n.4, p.315-335, Dec. 1994 [doi>10.1007/BF01018614]
• 16: Shriram Krishnamurthi. Programming Languages: Application and Interpretation. 2007. Version 2007-04-26.
• 17: Jacob Matthews , Robert bruce Findler, An operational semantics for scheme1, Journal of Functional Programming, v.18 n.1, p.47-86, January 2008 [doi>10.1017/S0956796807006478]
• 18: Philip K. McKinley , Seyed Masoud Sadjadi , Eric P. Kasten , Betty H. C. Cheng, Composing Adaptive Software, Computer, v.37 n.7, p.56-64, July 2004 [doi>10.1109/MC.2004.48]
• 19: Todd Millstein, Practical predicate dispatch, Proceedings of the 19th annual ACM SIGPLAN conference on Object-oriented programming, systems, languages, and applications, October 24-28, 2004, Vancouver, BC, Canada
• 20: Kurt Schelfthout , Tom Holvoet , Yolande Berbers, Views: customizable abstractions for contextaware applications in MANETs, Proceedings of the fourth international workshop on Software engineering for large-scale multi-agent systems, May 15-16, 2005, St. Louis, Missouri
• 21: Guy Steele, Common Lisp: The Language, Digital Press, Newton, MA, 1990
• 22: Éric Tanter, Expressive scoping of dynamically-deployed aspects, Proceedings of the 7th international conference on Aspect-oriented software development, March 31-April 04, 2008, Brussels, Belgium [doi>10.1145/1353482.1353503]
• 23: Éric Tanter, Kris Gybels, Marcus Denker, and Alexandre Bergel. Context-aware aspects. In Welf Löwe and Mario Südholt, editors, Proceedings of the 5th International Symposium on Software Composition (SC 2006), volume 4089 of Lecture Notes in Computer Science, pages 227-242, Vienna, Austria, March 2006. Springer-Verlag.
• 24: Aaron Mark Ucko. Predicate dispatching in the Common Lisp Object System. Technical Report AITR-2001-006, Massachusetts Institute of Technology, Artificial Intelligence Laboratory, Cambridge, MA, 2001.
• 25: Martin von Löwis , Marcus Denker , Oscar Nierstrasz, Context-oriented programming: beyond layers, Proceedings of the 2007 international conference on Dynamic languages: in conjunction with the 15th International Smalltalk Joint Conference 2007, August 25-31, 2007, Lugano, Switzerland [doi>10.1145/1352678.1352688]
• 26: Robert J. Walker , Gail C. Murphy, Implicit context: easing software evolution and reuse, Proceedings of the 8th ACM SIGSOFT international symposium on Foundations of software engineering: twenty-first century applications, p.69-78, November 06-10, 2000, San Diego, California, United States
• 27: Mitchell Wand , Gregor Kiczales , Christopher Dutchyn, A semantics for advice and dynamic join points in aspect-oriented programming, ACM Transactions on Programming Languages and Systems (TOPLAS), v.26 n.5, p.890-910, September 2004 [doi>10.1145/1018203.1018208]
• 28: Daniel Weinreb and David Moon. Flavors: Message passing in the Lisp machine. A.I. Memo 602, Massachussetts Institute of Technology, Artificial Intelligence Laboratory, 1980.
• 29: Mark Weiser, Some computer science issues in ubiquitous computing, Communications of the ACM, v.36 n.7, p.75-84, July 1993 [doi>10.1145/159544.159617]

INDEX TERMS

Primary Classification:
  D. Software
  D.3 PROGRAMMING LANGUAGES
      D.3.2 Language Classifications

Additional Classification:
  D. Software
  D.3 PROGRAMMING LANGUAGES
      D.3.1 Formal Definitions and Theory

General Terms:
Languages