39th Workshop on (Constraint and Functional) Logic Programming (WLP 2025)

September 24, 2025 in Évora, Portugal

Workshop at Declare 2025 (September 24-26, 2025 in Évora, Portugal)
and co-located with

Call for Papers WLP 2025

General

The Workshops on (Constraint) Logic Programming are the annual meeting of the German Society of Logic Programming Gesellschaft für Logische Programmierung e.V. (GLP) and brings together researchers interested in logic programming, constraint programming, answer set programming, and related areas like databases and artificial intelligence (not only from Germany).

The workshops provide a forum for exchanging ideas on declarative programming, especially logic, constraint logic and functional logic programming, nonmonotonic reasoning and knowledge representation, and facilitate interactions between research in theoretical foundations and in the design and implementation of logic-based programming systems.

The technical program of the workshop will include invited talks, presentations of refereed papers, and system demonstrations.

Previous WLP editions: WLP 2024 (Würzburg, Germany), WLP 2023 (Berlin, Germany), WLP 2022 (Trier, Germany), WLP 2021 (Berlin, Germany), WLP 2020 (Bamberg, Germany), WLP 2019 (Cottbus, Germany), WLP 2018 (Berlin, Germany), WLP 2017 (Würzburg, Germany), WLP 2016 (Leipzig, Germany), WLP 2015 (Dresden, Germany), WLP 2014 (Lutherstadt Wittenberg, Germany), WLP 2013 (Kiel, Germany), WLP 2012 (Bonn, Germany), WLP 2011 (Vienna, Austria), WLP 2010 (Cairo, Egypt), WLP 2009 (Potsdam, Germany), WLP 2008 (Dresden, Germany), WLP 2007 (Würzburg, Germany), WLP 2006 (Vienna, Austria), WLP 2005 (Ulm, Germany), WLP 2004 (Potsdam, Germany), WLP 2002 (Dresden, Germany), WLP 2001 (Kiel, Germany), WLP 2000 (Berlin, Germany), WLP 1999 (Würzburg, Germany), WLP 1998 (Vienna, Austria), WLP 1997 (Munich, Germany), WLP 1995 (Vienna, Austria)

Accepted Papers

Regular:
  • Sascha Rechenberger and Thom Frühwirth: Optimized Execution of FreeCHR Constraint Handling Rules (CHR) is a rule-based programming language that rewrites collections of constraints. It is typically embedded into a general-purpose language. There exists a plethora of implementations for numerous host languages. However, the existing implementations often re-invent the method of embedding, which impedes maintenance and weakens assertions of correctness. To formalize and thereby standardize the embedding of a ground subset of CHR into arbitrary host languages, we introduced the framework FreeCHR and proved it to be a valid representation of classical CHR. For the sake of simplicity, abstract implementations of our framework did not yet include a concrete matching algorithm nor optimizations. In this paper, we introduce an improved execution and matching algorithm for FreeCHR. We also provide empirical evaluation of the algorithm.
  • Michael Hanus and Steven Libby: Functional Logic Program Transformations Many tools used to process programs, like compilers, analyzers, or verifiers, perform some transformation on their intermediate program representation, like abstract syntax trees. Implementing such program transformation is a non-trivial task, since it is necessary to iterate over the complete syntax tree and apply various transformations at nodes in a tree. In this paper we show how the features of functional logic programming are useful to implement program transformations in a compact and comprehensible manner. For this purpose, we propose to write program transformations as partially defined and non-deterministic operations. Since the implementation of non-determinism usually causes some overhead compared to deterministically defined operations, we compare our approach to a deterministic transformation method. We evaluate these alternatives for the functional logic language Curry and its intermediate representation FlatCurry which is used in various analysis and verification tools and compilers.
Short:
  • Mario Wenzel: Improving Maintainability and Transparency in Student Data Pipelines Using Datalog This report describes the implementation of a Datalog-based application to find inconsistencies in a university student database. The implementation supersedes an existing approach using the ETL-tool "Pentaho Data Integration".

Important Dates

  • submission opens: May 10, 2025
  • Submission deadline: July 18th, 2025 (extended)
  • Notification of acceptance: August 8th, 2025
  • Final version : August 31th, 2025
  • workshop: September 24th, 2025

Topics

Contributions are welcome on all theoretical, experimental, and application aspects of logic programming (LP) and constraint programming (CP), including, but not limited to the following areas (the order does not reflect any priorities):

Logic Programming and Extensions

  • logic programming
  • constraint and constraint logic programming
  • functional logic programming
  • multi-paradigm declarative programming
  • implementation and extensions of declarative languages
  • foundations, semantics, specification, verification
  • dynamics, parallelism, concurrency

Knowledge Representation and Nonmonotonic Reasoning

  • deductive databases, data mining
  • knowledge representation, non-monotonic reasoning
  • rule-based systems
  • abductive and inductive logic programming
  • answer-set programming
  • semantics and proof-theoretical investigations

Application of Logic Programming

  • applications & project descriptions, e.g. in the fields planning, scheduling, configuration, computational law
  • logic programming in production, management, environment, education, medicine, internet, etc.
  • cp/lp for semantic web applications and reasoning on the semantic web
  • data modelling for the web, semistructured data, and web query languages
  • lessons learned by teaching in the addressed fields

Implementation of Systems

  • program analysis, abstract interpretation
  • program transformation, partial evaluation, meta-programming
  • interaction of declarative programming with other formalisms/ ai technologies
  • software techniques for declarative programming, programming environments and tools
  • system descriptions, comparisons, evaluations
  • benchmarks
  • implementation techniques
  • software techniques and programming support (e.g., types, modularity, design patterns, debugging, testing, systematic program development).

PC Chair

Program Committee

Submission Details

Authors are invited to submit papers in the following categories:

  • extended abstract (no longer than 12 pages including figures and references) or
  • system description (no longer than 6 pages, excluding references)

via the EasyChair submission website for WLP 2025.

Papers must describe original work, be written and presented in English, and must not substantially overlap with papers that have been published or that are simultaneously submitted to a journal, conference, or workshop with refereed proceedings. However, work that already appeared in unpublished or informally published workshops proceedings may be submitted, too.

Workshop languages are German and English.

Proceedings (to be confirmed)

All accepted papers will be published as a technical report and made available electronically at the workshop. As for previous events, it is planned to publish selected papers as post-conference proceedings.

Registration, Travel

see Declare 2025

Sibylle Schwarz | HTWK Leipzig