[PDF] On understanding types, data abstraction, and polymorphism | Semantic Scholar

This dissertation proposes type intervals as a unifying concept for expressing (1--3) and other related constructs and develops an extension of F-omega with interval kinds as a formal theory of higher-order subtyping with type intervals, and shows how the familiar concepts ofHigher-order bounded quantification, bounded operator abstraction and singleton kinds can all be encoded in a semantics-preserving way using interval kinds.

An extension to the type system of ML that captures the polymorphic nation of field selection together with a techniques that generalizes relational operators to arbitrary data structures provides a statically typed language in which generalized relational databases may be cleanly represented as typed structures.

Two new approaches to the polymorphic typing of these non-applicative features of ML with imperative features proposed so far are studied, one of which relies on switching to "by-name" semantics for the constructs of polymorphism, instead of the usual " by-value" semantics.

Contextual polymorphism is a variant of parametric polymorphism that is based on contexts, which are abstractions of collections of declarations, and assertions, which link polymorphic routines to the environments that call them.

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It is suggested in the conclusion that the understanding of abstraction for object-oriented languages and of other language design, implementation, and environment issues will have progressed sufficiently by 1985 to warrant the design of a successor to Ada by the late 1980s.

Type inference, the process of assigning types to untyped expressions, may be motivated by the design of a typed language or semantical considerations on the meanings of types and expressions, or by a general class of semantic models of type inference.

This work uses typed lambda calculus with bindings, declarations, and types as first-class values to build modules, interfaces and implementations, abstract data types, generic types, recursive types, and unions in a concise operational semantics given by inference rules.

This paper shows that unless the use of such parameterized definitions is restricted, new (unparameterized) types may be defined which more closely resemble deterministic context-free languages.