An Algebraic Theory of Polymorphic Temporal Media -- Supporting Decisions in Complex, Uncertain Domains with Declarative Languages -- A Typeful Approach to Object-Oriented Programming with Multiple Inheritance -- Compositional Model-Views with Generic Graphical User Interfaces -- An Implementation of Session Types -- UUXML: A Type-Preserving XML Schema–Haskell Data Binding -- Improved Compilation of Prolog to C Using Moded Types and Determinism Information -- A Generic Persistence Model for (C)LP Systems (and Two Useful Implementations) -- Pruning in the Extended Andorra Model -- USA-Smart: Improving the Quality of Plans in Answer Set Planning -- : A System for Reasoning about Answer Set Programs in Prolog -- Simplifying Dynamic Programming via Tabling -- Symbolic Execution of Behavioral Requirements -- Observing Functional Logic Computations -- Parametric Fortran – A Program Generator for Customized Generic Fortran Extensions -- Typing XHTML Web Applications in ML -- Implementing Cut Elimination: A Case Study of Simulating Dependent Types in Haskell.

The International Symposium on Practical Aspects of Declarative Languages (PADL) is a forum for researchers and practitioners to present original work emphasizing novel applications and implementation techniques for all forms of declarative concepts, especially those emerging from functional, logic, and c- straint languages. Declarative languages have been studied since the inception of computer science, and continue to be a vibrant subject of investigation today due to their applicability in current application domains such as bioinformatics, network con?guration, the Semantic Web, telecommunications software, etc. The 6th PADL Symposium was held in Dallas, Texas on June 18–19, 2004, and was co-located with the Compulog-Americas Summer School on Compu- tional Logic. From the submitted papers, the program committee selected 15 for presentation at the symposium based upon three written reviews for each paper, which were provided by the members of the program committee and additional referees. Two invited talks were presented at the conference. The ?rst was given by Paul Hudak (Yale University) on “An Algebraic Theory of Polymorphic T- poral Media. ” The second invited talk was given by Andrew Fall (Dowlland Technologies and Simon Fraser University) on “Supporting Decisions in C- plex, Uncertain Domains with Declarative Languages. ” Following the precedent set by the previous PADL symposium, the program committee this year again selected one paper to receive the ‘Most Practical - per’award.