Thisvolumecontainsaselectionofthepaperspresentedatthe18thInternational Workshop on Functional and (Constraint) Logic Programming (WFLP 2009), held on June 28, 2009 in Bras ?lia, Brazil. Previous WFLP meetings were held in Siena (2008), Paris (2007), Madrid (2006), Tallinn (2005), Aachen (2004), Valencia (2003), Grado(2002), Kiel(2001), Benicassim(2000), Grenoble(1999), Bad Honnef (1998), Schwarzenberg (1997, 1995, and 1994), Marburg (1996), Rattenberg (1993), and Karlsruhe (1992). The aim of the WFLP series is to bring together researchers interested in functional programming, (constraint) logic programming, as well as the integ- tion of the two paradigms. It promotes the cross-fertilizing exchange of ideas and experiences among researchers and students from the di?erent commu- ties interested in the foundations, applications, and combinations of high-level, declarative programming languages and related areas. WFLP 2009 solicited papers in all areas of functional and (constraint) logic programming, including but not limited to: - Foundations: formalsemantics, rewritingandnarrowing, non-monotonicr- soning, dynamics, and type theory. - Language Design: modules and type systems, multi-paradigm languages, concurrency and distribution, and objects. - Implementation: abstract machines, parallelism, compile-time and run-time optimizations, and interfacing with external languages. - Transformation and Analysis: abstract interpretation, specialization, partial evaluation, program transformation, and meta-programming. - Software Engineering: design patterns, speci?cation, veri?cation and vali- tion, debugging, and test generation. - IntegrationofParadigms: integrationofdeclarativeprogrammingwithother paradigms such as imperative, object-oriented, concurrent, and real-time programming. - Applications: declarative programming in education and industry, doma- speci?c languages, visual/graphical user interfaces, embedded systems, WWW applications, knowledge representation and machine learning, - ductive databases, advanced programming environments and t

This book constitutes selected papers from the 12th International Workshop on Rewriting Logic and Its Applications, WRLA 2020, held in Dublin, Ireland, in April 2020.Due to the COVID-19 pandemic the workshop took place virtually. The 11 full papers presented in this volume were carefully reviewed and selected from 16 submissions Rewriting logic is a natural model of computation and an expressive semantic framework for concurrency, parallelism, communication, and interaction. It can be used for specifying a wide range of systems and languages in various application fields.

This book constitutes the thoroughly refereed post-workshop proceedings of the 10th International Workshop on Rewriting Logic and its Applications, WRLA 2014, held as a satellite event of ETAPS 2014, in Grenoble, France, in March 2014. The 13 revised full papers presented together with 3 invited papers were carefully reviewed and selected from 21 submissions. The papers address a great diversity of topics in the fields of foundations and models of RL; languages based on RL; RL as a logical framework; RL as a semantic framework; use of RL to provide rigorous support for model-based software engineering; formalisms related to RL; verification techniques for RL specifications; comparisons of RL with existing formalisms having analogous aims; application of RL to specification and analysis of distributed systems and physical systems.