Preface

Declarative languages build on sound theoretical bases to provide attractive frame- works for application development. These languages have been successfully applied to many different real-world situations, ranging from database management to active networks to software engineering to decision support systems. New developments in theory and implementation have opened up new application areas. At the same time, applications of declarative languages to novel problems raise numerous interesting research issues. Well-known questions include designing for scalability, language extensions for application deployment, and programming envi- ronments. Thus, applications drive the progress in the theory and implementation of declarative systems, and benefit from this progress as well. PADL is a forum for researchers and practitioners to present original work emphasizing novel applications and implementation techniques for all forms of declarative concepts, including, functional, logic, constraints, etc. This book collects the contributions accepted for publication at the 18th Interna- tional Symposium on Practical Aspects of Declarative Languages (PADL 2016), held in St. Petersburg, Florida, USA, during January 18–19, 2016. Originally established as a workshop (PADL 1999 in San Antonio, Texas), the PADL series developed into a regular annual symposium; the preceding editions took place in San Antonio, Texas (1999), Boston, Massachusetts (2000), Las Vegas, Nevada (2001), Portland, Oregon (2002), New Orleans, Louisiana (2003), Dallas, Texas (2004), Long Beach, California (2005), Charleston, South Carolina (2006), Nice, France (2007), San Francisco, California (2008), Savannah, Georgia (2009), Madrid, Spain (2010), Austin, Texas (2012), Rome, Italy (2013), San Diego, California (2014), and Portland, Oregon (2015). PADL 2016 was organized by the Association for Logic Programming (ALP), in collaboration with the Organizing Committees of the co-located events at the Sym- posium on Principles of Programming Languages (POPL 2016), the Department of Engineering at the University of Ferrara (Italy), and the Department of Computer Science at the University of Chicago (USA). The conference received 17 submissions. Each paper was carefully reviewed by at least three members of the Program Committee. In all, 11 papers were selected and are presented in these proceedings. The chairs wish to thank the reviewers for their careful work in selecting the best papers, the ALP and ACM for the support, and Gopal Gupta for his help with the organization.