Adding Alternative Access Paths to Abstract Data Types

Abstract

We present in this paper a proposal for developing efficient programs in the abstract data type (ADT) programming framework, keeping the modular structure of programs and without violating the information hiding principle. The proposal focuses in the concept of “shortcut” as an efficient way of accessing to data, alternative to the access by means of the primitive operations of the ADT. We develop our approach in a particular ADT, a store of items. We define shortcuts in a formal manner, using algebraic specifications interpreted with initial semantics, and so the result has a well-defined meaning and fits in the ADT framework. Efficiency is assured with an adequate representation of the type, which provides O(1) access to items in the store without penalising the primitive operations of the ADT.