The 16th International Workshop on Implementation and Application of Fu- tional Languages (IFL 2004) was held in Lub ] eck, Germany, September 8 10, 2004. It was jointly organized by the Institute of Computer Science and Applied Mathematics of the University of Kiel and the Institute of Software Technology and Programming Languages of the University of Lub ] eck. IFL 2004 was the sixteenth event in the annual series of IFL workshops. The aim of the workshop series is to bring together researchers actively engaged in the implementation and application of functional and function-based progr- ming languages. It provides an open forum for researchers who wish to present and discuss new ideas and concepts, work in progress, preliminary results, etc., related primarily, but not exclusively, to the implementation and application of functional languages. Topics of interest cover a wide range from theoretical - pects over language design and implementation towards applications and tool support. Previous IFL workshops were held in the United Kingdom (Southampton, Norwich, London, St Andrews, and Edinburgh), in the Netherlands (Nijmegen and Lochem), in Germany (Aachen and Bonn), in Sweden (B? astad and Sto- holm), and in Spain (Madrid). In 2005, the 17th International Workshop on - plementation and Application of Functional Languages will be held in Dublin, Ireland."

Functional programminghas a long history, reaching back through early reali- tions in languages like LISP to foundational theories of computing, in particular ?-calculus and recursive function theory. In turn, functional programming has had wide in?uence in computing, both through developments within the dis- pline, such as formal semantics, polymorphic type checking, lazy evaluation and structural proof, and as a practical embodiment of formalized approaches, such as speci?cation, transformation and partial application. One of the engaging features of functional programming is precisely the crossover between theory and practice. In particular, it is regarded as ess- tial that all aspects of functional programming are appropriately formalized, especially the speci?cation and implementation of functional languages. Thus, specialist functional programming events like the International Workshop on the Implementation of Functional Languages (IFL) attract contributions where strong use is made of syntactic, semantic and meta-mathematical formalisms to motivate, justify and underpin very practical software systems. IFL grew out of smaller workshops aimed at practitioners wrestling with the nuts and bolts of making concrete implementations of highly abstract l- guages. Functional programming has always been bedeviled by an unwarranted reputation for slowand ine?cient implementations. IFL is one venue where such problemsaretackledheadon, alwaysusing formaltechniques to justify practical implementation

This volume provides a state of the art survey of research trends in parallel functional programming. The text is divided into two sections: the first section gives comprehensive introductions to key issues such as: foundations, programming constructs, proof, architectures, and implementations; the second comprises shorter summaries of research areas which are either of particular interest at the moment, or which promise to provide key developments in the near future. Topics covered here include: coordination languages, performance monitoring; data flow programming; explicit parallelism; BSP and cost modelling. Contributions have been commissioned by key researchers and practitioners in the area, including several from the US and Canada where this is an area of increasing interest. Research Directions in Parallel Functional Programming will be of interest to researchers, (post)graduate students and practitioners in all relevant areas.

Functional programming is rooted in lambda calculus, which constitutes the world's smallest programming language. This well-respected text offers an accessible introduction to functional programming concepts and techniques for students of mathematics and computer science. The treatment is as nontechnical as possible, and it assumes no prior knowledge of mathematics or functional programming. Cogent examples illuminate the central ideas, and numerous exercises appear throughout the text, offering reinforcement of key concepts. All problems feature complete solutions.