Extensible encoding of type hierarchies

The subtyping test consists of checking whether a type t is a descendant of a type r (Agrawal et al. 1989). We study how to perform such a test efficiently, assuming a dynamic hierarchy when new types are inserted at run-time. The goal is to achieve time and space efficiency, even as new types are inserted. We propose an extensible scheme, named ESE, that ensures (1) efficient insertion of new types, (2) efficient subtyping tests, and (3) small space usage. On the one hand ESE provides comparable test times to the most efficient existing static schemes (e.g., Zibin et al. (2001)). On the other hand, ESE has comparable insertion times to the most efficient existing dynamic scheme (Baehni et al. 2007), while ESE outperforms it by a factor of 2-3 times in terms of space usage. Categories and Subject Descriptors D.3.3 [PROGRAMMING LANGUAGES]: Language Constructs and Features General Terms Languages, Algorithms Keywords Subtyping Test, Dynamic Loading

• Type: Conference
• Year: 2008
• Where: POPL
• Authors: Hamed Seiied Alavi, Seth Gilbert, Rachid Guerraoui
• Keywords: Features General Terms, Keywords Subtyping Test, POPL 2008, Programming Languages, Small Space Usage