ECOOP 2020
Dates and location to be announced

The aim of the paper is to provide solid foundations for a programming paradigm natively supporting the creation and manipulation of cyclic data structures. To this end, we describe coFJ, a Java-like calculus where objects can be \emph{infinite} and methods are equipped with a \emph{codefinition} (an alternative body). We provide an abstract semantics of the calculus based on the framework of \emph{inference systems with corules}. In coFJ with this semantics, FJ recursive methods on finite objects can be extended to infinite objects as well, and behave as desired by the programmer, by specifying a codefinition. In the meantime, we describe an operational semantics which can be directly implemented in a programming language, and prove the soundness of such semantics with respect to the abstract one.