Abstract

: We give a semantics for a typed object calculus, an extension of System F with object subsumption and method override. We interpret the calculus in a per model, proving the soundness of both typing and equational rules. This semantics suggests a syntactic translation from our calculus into a simpler calculus with neither subtyping nor objects. 1. Objects, Records, and Functions Despite the many formal accounts of object-oriented languages, the meaning and the properties of object types remain unclear. In particular, the soundness of object subtyping depends on invariants difficult to capture with standard type constructions; attempts based on record types have been inspiring but not compelling. In order to study object types in a clear setting, we give semantics to an extension of Girard's System F [Girard, Lafont, Taylor 1989] with subtyping, recursion, and some basic object constructs. Like all common object-oriented languages, this calculus supports object subsumption and metho...

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