OOlong: A Concurrent Object Calculus for Extensibility and Reuse Elias Castegren Tobias Wrigstad KTH Royal Institute of Technology Uppsala University Kista, Sweden Uppsala, Sweden
[email protected] [email protected] ABSTRACT This avoids tying the language to a specific model of class We present OOlong, an object calculus with interface in- inheritance (e.g., Java's), while still maintaining an object- heritance, structured concurrency and locks. The goal of oriented style of programming. Concurrency is modeled in a the calculus is extensibility and reuse. The semantics are finish/async style, and synchronisation is handled via locks. therefore available in a version for LATEX typesetting (written The semantics are provided both on paper and in a mecha- in Ott), a mechanised version for doing rigorous proofs in nised version written in Coq. The paper version of OOlong Coq, and a prototype interpreter (written in OCaml) for is defined in Ott [25], and all typing rules in this paper are typechecking an running OOlong programs. generated from this definition. To make it easy for other researchers to build on OOlong, we are making the sources of both versions of the semantics publicly available. We also CCS Concepts provide a prototype interpreter written in OCaml. •Theory of computation ! Operational semantics; Concur- rency; Interactive proof systems; •Software and its engineer- With the goal of extensibility and re-usability, we make the ing ! Object oriented languages; Concurrent programming following contributions: structures; Interpreters; • We define the formal semantics of OOlong, motivate the choice of features, and prove type soundness (Sections Keywords 2{5). Object Calculi; Semantics; Mechanisation; Concurrency • We provide a mechanised version of the full semantics and soundness proof, written in Coq (Section 6).