A lambda-calculus for dynamic binding

AbstractDynamic binding is a runtime lookup operation which extracts values corresponding to some “names” from some “environments” (finite, unordered associations of names and values). Many situations related with flexible software assembly involve dynamic binding: first-class modules, mobile code, object-oriented message passing. This paper proposes λN, a compact extension of the λ-calculus to model dynamic binding, where variables are labelled by names, and where arguments are passed to functions along named channels. The resulting formalism preserves familiar properties of the λ-calculus, has a Curry-style-type inference system, and has a formal notion of compatibility for reasoning about extensible environments. It can encode records and record extensions, as well as first-class contexts with context-filling operations, and therefore provides a basic framework for expressing a wide range of name-based coordination mechanisms. An experimental functional language based on λN illustrates the exploitation of dynamic binding in programming language design