Two Level Functional Languages

The authors describe here a framework in which the type notation of functional languages is extended to include a notation for binding times (that is run-time and compile-time) that distinguishes between them. Consequently, the ability to specify code and verify program correctness can be improved. Two developments are needed, the first of which introduces the binding time distinction into the lambda calculus in a manner analogous with the introduction of types into the untyped lambda calculus. Methods are also presented for introducing combinators for run-time. The second concerns the interpretation of the resulting language, which is known as the mixed lambda-calculus and combinatory logic. The notion of "parametrized semantics" is used to describe code generation and abstract interpretation. The code generation is for a simple abstract machine designed for the purpose, it is close to the categorical abstract machine. The abstract interpretation focuses on a strictness analysis that generalizes Wadler's analysis for lists. It is also shown how the results of abstract interpretation may be used to improve the code generation.

This book provides a framework in which the type notation of functional languages is extended to include a distinguishing notation for run-times and compile-times.

This book constitutes the thoroughly refereed post-conference proceedings of the 23rd International Symposium on Implementation and Application of Functional Languages, IFL 2011, held in Lawrence, Kansas, USA, in October 2011. The 11 revised full papers presented were carefully reviewed and selected from 33 submissions. The papers by researchers and practitioners who are actively engaged in the implementation and the use of functional and function based programming languages describe practical and theoretical work as well as applications and tools. They discuss new ideas and concepts, as well as work in progress and results.

The Glasgow functional programming group has held a workshop each summer since 1988. The entire group, accompanied by a selection of colleagues from other institutions, retreats to a pleasant Scottish location for a few days. Everyone speaks briefly, enhancing coherence, cross fertilisation, and camaraderie in our work. The proceedings of the first workshop were published as a technical report. Demand for this was large enough to encourage wider publication, and subsequent proceedings have been published in the Springer-Verlag Workshops in Computing series. These are the proceedings of the-meeting held 12-14 August 1991, in Portree on the Isle of Skye. A preliminary proceedings was prepared in advance of the meeting. Most presentations were limited to a brief fifteen minutes, outlining the essentials of their subject, and referring the audience to the pre-print proceedings for details. Papers were then refereed and rewritten, and you hold the final results in your hands. A number of themes emerged at this year's workshop, including relational algebra and its application to hardware design, partial evaluation and program transformation, implementation techniques, and strictness analysis. We were especially pleased to see applications of functional programming emerge as a theme. One of the sessions was devoted to a lively discussion of applications, and was greatly enhanced by our industrial participants. The workshop was organised by Kei Davis, Cordelia Hall, Rogardt Heldal, Carsten Kehler Holst, John Hughes, John O'Donnell, and Satnam Singh all from the University of Glasgow.

This volume presents eight carefully revised texts of selected lectures given by leading researchers of the field at the first Central European Functional Programming School, CEFP 2005, held in Budapest, Hungary, in July 2005. The eight revised full papers presented were carefully selected during two rounds of reviewing and improvement for inclusion in the book. The lectures cover a wide range of topics such as new programming language concepts for subtyping.

This book offers a comprehensive view of the best and the latest work in functional programming. It is the proceedings of a major international conference and contains 30 papers selected from 126 submitted. A number of themes emerge. One is a growing interest in types: powerful type systems or type checkers supporting overloading, coercion, dynamic types, and incremental inference; linear types to optimize storage, and polymorphic types to optimize semantic analysis. The hot topic of partial evaluation is well represented: techniques for higher-order binding-time analysis, assuring termination of partial evaluation, and improving the residual programs a partial evaluator generates. The thorny problem of manipulating state in functional languages is addressed: one paper even argues that parallel programs with side-effects can be "more declarative" than purely functional ones. Theoretical work covers a new model of types based on projections, parametricity, a connection between strictness analysis and logic, and a discussion of efficient implementations of the lambda-calculus. The connection with computer architecture and a variety of other topics are also addressed.

This book constitutes the thoroughly refereed post-proceedings of the 20th International Workshop on Implementation and Applications of Functional Languages, IFL 2008, held in Hatfield, UK, in September 2008. The 15 revised full papers presented were carefully reviewed and selected from 31 submissions. Topics of interest cover a wide range from novel language designs, theoretical underpinnings, compilation and optimisation techniques for diverse hardware architectures, to applications, programming techniques and novel tools.