A Lambda Calculus of Objects with Self-Inflicted Extension

Pietro Di Gianantonio (1) , Furio Honsell (1) , Luigi Liquori (1, 2, 3)

1 DIMI - Dipartimento di Matematica e Informatica - Universita Udine
2 ENS de Lyon - École normale supérieure de Lyon
3 LOGNET - Logical Networks: Self-organizing Overlay Networks and Programmable Overlay Computing Systems

In this paper we investigate, in the context of functional prototype-based languages, objects which might extend themselves upon receiving a message. The possibility for an object of extending its own " self " , referred to by Cardelli, as a self-inflicted operation, is novel in the context of typed object-based languages. We present a sound type system for this calculus which guarantees that evaluating a well-typed expression will never yield a message-not-found run-time error. We give several examples which illustrate the increased expressive power of our system with respect to existing calculi of objects. The new type system allows also for a flexible width-subtyping, still permitting sound method override, and a limited form of object extension. The resulting calculus appears to be a good starting point for a rigorous mathematical analysis of class-based languages.

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

Pietro Di Gianantonio, Furio Honsell, Luigi Liquori. A Lambda Calculus of Objects with Self-Inflicted Extension. Proceedings of the 13th ACM SIGPLAN conference on Object-oriented programming, systems, languages, and applications, OOPSLA '98, Vancouver, BC, Canada, Oct 1998, Vancouver, BC, Canada. pp.166--178, ⟨10.1145/286936.286955⟩. ⟨hal-01154180⟩