Programming languages are programmers' most basic tools. With appropriate programming languages one can drastically reduce the cost of building new applications as well as maintaining existing ones. During the last decades, there have been many language-related advances in traditional programming paradigms such as functional, logic, and object-oriented programming, as well as the development of new paradigms such as aspect-oriented programming. The main driving force was and will be to better express programmers' ideas. Therefore, research in programming languages is an endless activity and the core of computer science. New language features, new programming paradigms, and better compile-time and run-time mechanisms can be foreseen in the future.

The aims of the 1 Workshop on Advances in Programming Languages (WAPL '07) was to provide a forum for exchange of ideas and experience in topics related to programming languages and systems. Original papers and implementation reports have been invited in all areas of programming languages. Major topics of interest included: automata theory and applications, compiling techniques, domain-specific languages, formal semantics and syntax, generative and generic programming, grammarware and grammar-based systems, knowledge engineering languages, integration of knowledge engineering and software engineering, languages and tools for trustworthy computing, language theory and applications, language concepts, design and implementation, markup languages (XML), metamodeling and modeling languages, model-driven engineering languages and systems, practical experiences with programming languages, program analysis, optimization and verification, program generation and transformation, programming paradigms (aspect-oriented, functional, logic, object-oriented, etc.), programming tools and environments, proof theory for programs, specification languages, type systems, virtual machines and just-in-time compilation, and visual programming languages. The WAPL '07 was held on th October 15 , 2007 in Wisla, Poland, as a part of International Multiconference of Computer Science and Information Technology (IMCSIT '07). Twenty papers were submitted to the workshop and the international program committee accepted eleven regular papers for oral presentation and four poster papers. Thus, the acceptance rate for regular papers was 55%. WAPL '07 consisted of three oral sessions, one poster session and an invited talk by Prof. Jan Madey from University of Warsaw. His talk on »Specification languages versus programming languages - a historical perspective« was also IMCSIT '07 conference opening keynote speech.

This special issue contains 8 papers, which have been selected from WAPL '07. These papers are extensively revised versions of original presentations published in IMCSIT '07 proceedings.

Gernot Gebhard and Philipp Lucas in their paper "OORS: An Object-Oriented Rewrite System" describe how retargeting a compiler's back end to a new architecture can be done more efficiently. Using the OORS language, a compiler developer can express the code generation and optimization phase in terms of cost-annotated rewrite rules supporting complex non-linear matching and replacing patterns. By profile inheritance mechanism the reuse of existing specification is achieved.

Koen Vanderkimpen, Marko van Dooren, and Eric Steegmans in their paper »Using Customizable Properties to Make Object Representation a First-class Citizen« present several language constructs that introduce properties as the first class citizen in an object-oriented language. Properties allow redefining object’s attributes in ways similar to redefinition of virtual methods in object-oriented languages.

Uwe Naumann and Jan Riehme in their paper »On Syntax-Directed Adjoint Fortran Code« present an alternative approach to improve the efficiency of high-dimensional function computation. This alternative is based on syntax-directed translation (L-attributed grammar) of a subset of Fortran to adjoint code.

Julien Cervelle, Rémi Forax, and Gilles Roussel in their paper »A Simple Implementation of Grammar Libraries« describe an extension of the Tatoo compiler - compiler that supports separate compilation of formal grammars. The approach allows the developer to define reusable libraries of grammars with the aim to simplify the development of domain specific languages.

Slavica Aleksic, Ivan Lukovic, Pavle Mogin, and Miro Govedarica in their paper »A Generator of SQL Schema Specifications« describe a generator of SQL schema specifications which is a part of IIS*Case tool. The main contribution of the paper is to show that fully operational applications can be built without manual coding of programs written in general-purpose or domain-specific languages.

Daniela da Cruz, Pedro Rangel Henriques, and Maria Joao Varanda Pereira in their paper »Constructing Program Animations Using a Pattern-Based Approach« present a generic approach to program visualization and animation. The approach uses well-known compiler techniques to inspect the source code in order to extract the necessary information to visualize it and understand the program execution.

Ján Kollár, Jaroslav Porubän, Peter Václavák, Jana Bandáková, and Michal Forgác in their paper »Functional Approach to the Adaptation of Languages instead of Software Systems« proposed the development of adaptive language processors that can vary the semantics of a program written in a given language with the aim to evolve software systems dynamically.

Dariusz Rzonca, Jan Sadolewski, and Bartosz Trybus in their paper »Prototype Environment for Controller Programming in the IEC 61131-3 ST Language« describe a prototyped ST compiler for programming industrial controllers. The distinguishing feature of the proposed implementation is a universal executable code that can be executed on different target platforms.

In conclusion, we hope the papers in this special issue will provide readers with the glimpse of current research trends in programming languages. I would like to thank all the authors for their valuable contributions. Another important success factor in the project were the referees. Our thanks go to Fei Cao, Thomas Cleenewerck, Johan Fabry, Pedro Rangel Henriques, Jan Kollar, Tomaž Kosar, Jan Madey, Pablo Martinez Lopez, Ivan Lukovic, Terence Parr, Gilles Roussel, Vladimir Safonov, Jose Luis Sierra, Boštjan Slivnik, Maria Joao Varanda Pereira, Dániel Varró, Jurgen Vinju, and Xiaoqing Wu.

Last but not the least, I am grateful for the support from Prof. Maria Ganzha and Prof. Marcin Paprzycki, IMCSIT' 07 organizers, and from Prof. Ivan Lukovic, Editor-in-Chief of ComSIS, who kindly accepted the request to publish the best WAPL '07 papers in this journal.

Guest Editor
Marjan Mernik
WAPL '07 chair, University of Maribor, Slovenia