Oege de Moor, Damien Sereni, Mathieu Verbaere, Elnar Hajiyev, Pavel Avgustinov, Torbjörn Ekman, Neil Ongkingco, Julian Tibble. .QL: Object-Oriented Queries Made Easy. In Ralf Lämmel, Joost Visser, João Saraiva, editors, Generative and Transformational Techniques in Software Engineering II, International Summer School, GTTSE 2007. Volume 5235 of Lecture Notes in Computer Science, pages 78-133, Springer, Braga, Portugal, 2007. [doi]
These notes are an introduction to .QL, an object-oriented query language for any type of structured data. We illustrate the use of .QL in assessing software quality, namely to find bugs, to compute metrics and to enforce coding conventions. The class mechanism of .QL is discussed in depth, and we demonstrate how it can be used to build libraries of reusable queries.