Higher-Order and Symbolic Computation, 17(4)

Editorial

Olivier Danvy and Ian Mason

The present issue is composed of three contributed articles.

In "Continuations and Web Servers," Christian Queinnec pioneers the use of continuations in the context of web applications. He proposes a new understanding of the interaction between a web server and its client during the execution of an interactive web application. Servers and clients are viewed as coroutines where the server passes its continuation to the client each time it passes control to it, and receives its continuation back when the client returns control to the server. A preliminary version of this work was presented at ICFP 2000 [2]

Power analysis aims at detecting invariants of the form "at this point, variable 'x' always denotes values of the form 'c^e', where each of 'c' and 'e' satisfies a static property." In "Algebraic Power Analysis by Abstract Interpretation," Isabella Mastroeni takes this theory to great generality and shows how to establish such invariants by using non-standard execution over appropriate abstract domains, i.e., abstract interpretation. A preliminary version of this work was presented at PADO 2001 [1].

In "Bisimilarity for the Region Calculus," Simon Helsen defines an equational theory for Tofte and Talpin's region calculus, a typed lambda calculus enriched with annotations for static memory management [3]. He develops an elegant bisimulation equivalence for this region calculus, and relates this notion of equivalence to the more traditional Morris variety.

Finally, we would like to heartily welcome two new associate editors: Kent R. Dybvig and Patricia Johann. Like the other associate editors, they can both identify relevant papers and manage the reviewing process. This freedom and this responsability are parts of what makes HOSC both a scholarly and collegial forum.

References

1. Mastroeni, I.: 2001, `Numerical Power Analysis'. In: O. Danvy and A. Filinski (eds.): Programs as Data Objects, Second Symposium (PADO 2001). Aarhus, Denmark, pp. 117-137.

2. Queinnec, C.: 2000, `The influence of browsers on evaluators or, continuations to program web servers'. In: P. Wadler (ed.): Proceedings of the 2000 ACM SIGPLAN International Conference on Functional Programming. Montreal, Canada, pp. 23-33.

3. Tofte, M., L. Birkedal, M. Elsman, and N. Hallenberg: 2004, `A Retrospective on Region-Based Memory Management'. Higher-Order and Symbolic Computation 17(3), 245-265.
[picture of journal cover]

September 2004 - hosc@brics.dk