A Subtyping for Extensible, Incomplete Objects

Viviana Bono (1) , Michele Bugliesi (2) , Mariangiola Dezani-Ciancaglini (1) , Luigi Liquori (3, 4, 5)

1 Dipartimento di Informatica [Torino]
2 Dipartimento di Matematica [padova]
3 ENSMN - Ecole Nationale Supérieure des Mines de Nancy
4 ECOO - Environment for cooperation
5 LOGNET - Logical Networks: Self-organizing Overlay Networks and Programmable Overlay Computing Systems

We extend the type system for the Lambda Calculus of Objects [16] with a mechanism of width subtyping and a treatment of incomplete objects. The main novelties over previous work are the use of subtype-bounded quantification to capture a new and more direct rendering of MyType polymorphism, and a uniform treatment for other features that were accounted for via different systems in subsequent extensions [7, 6] of [16]. The new system provides for (i) appropriate type specialization of inherited methods, (ii) static detection of errors, (iii) width subtyp-ing compatible with object extension, and (iv) sound typing for partially specified objects.

Mots clés: Objects; Type System; Subtyping; Type Soundness

Domaines: Informatique et langage [cs.CL]; Logique en informatique [cs.LO]

Viviana Bono, Michele Bugliesi, Mariangiola Dezani-Ciancaglini, Luigi Liquori. A Subtyping for Extensible, Incomplete Objects. Fundamenta Informaticae, 1999, 38 (4), pp.325--364. ⟨hal-01153734⟩