FHJ: A Formal Model for Hierarchical Dispatching and Overriding
Multiple inheritance is a valuable feature for Object-Oriented Programming. However, it is also tricky to get right, as illustrated by the extensive literature on the topic. A key issue is the ambiguity arising from inheriting multiple parents, which can have conflicting methods. Numerous existing work provides solutions for conflicts which arise from diamond inheritance: i.e. conflicts that arise from implementations sharing a common ancestor. However, most mechanisms are inadequate to deal with unintentional method conflicts: conflicts which arise from two unrelated methods that happen to share the same name and signature. This paper presents a new model called Featherweight Hierarchical Java (FHJ) that deals with unintentional method conflicts. In our new model, which is partly inspired by C++, conflicting methods arising from unrelated methods can coexist in the same class, and hierarchical dispatching supports unambiguous lookups in the presence of such conflicting methods. To avoid ambiguity, hierarchical information is employed in method dispatching, which uses a combination of static and dynamic type information to choose the implementation of a method at run-time. Furthermore, unlike all existing inheritance models, our model supports hierarchical method overriding: that is, methods can be independently overridden along the multiple inheritance hierarchy. We give illustrative examples of our language and features and formalize FHJ as a minimal Featherweight-Java style calculus.
Fri 20 JulDisplayed time zone: Amsterdam, Berlin, Bern, Rome, Stockholm, Vienna change
16:00 - 17:15 | |||
16:00 25mResearch paper | FHJ: A Formal Model for Hierarchical Dispatching and Overriding ECOOP Research Papers Yanlin Wang University of Hong Kong, Haoyuan Zhang , Bruno C. d. S. Oliveira University of Hong Kong, China, Marco Servetto Victoria University of Wellington DOI | ||
16:25 25mResearch paper | Modeling infinite behaviour by corules ECOOP Research Papers Davide Ancona University of Genova, Francesco Dagnino DIBRIS, University of Genova, Italy, Elena Zucca University of Genova DOI | ||
16:50 25mResearch paper | The Essence of Nested Composition ECOOP Research Papers Xuan Bi The University of Hong Kong, Bruno C. d. S. Oliveira University of Hong Kong, China, Tom Schrijvers KU Leuven DOI |