A facility for defining and manipulating generalized data structures

Abstract

A data structure definition facility (DSDF) is described that provides definitions for several primitive data types, homogeneous and heterogeneous arrays, cells, stacks, queues, trees, and general lists. Each nonprimitive data structure consists of two separate entities—a head and a body. The head contains the entry point(s) to the body of the structure; by treating the head like a cell, the DSDF operations are capable of creating and manipulating very general data structures. A template structure is described that permits data structures to share templates. The primary objectives of the DSDF are: (1) to develop a definition facility that permits the programmer to explicitly define and manipulate generalized data structures in a consistent manner, (2) to detect mistakes and prevent the programmer from creating (either inadvertently or intentionally) undesirable (or illegal) data structures, (3) to provide a syntactic construction mechanism that separates the implementation of a data structure from its use in the program in which it is defined, and (4) to facilitate the development of reliable software.