Group-Based Fields

This paper reports the preliminary work on extending the concept of collection in 81/2. 81/2 is a declarative language that allows the functional definition of streams and collections [1, 2]. In this paper, we focus our interest on a high-level programming abstraction which extends the concept of collection in 81/2. The new construct is based on an algebra of index set, called shape, and an extension of the array type, the field type. The rest of this paper has the following structure. Section 2 gives some background on collections and arrays. Some shortcomings of data-parallel arrays are sketched. Section 3 describes the 81/2 answers to the previous problem and introduces group-based shapes and fields. Section 4 is devoted to the shape algebra. Section 5 introduces the main field operations and field definitions. Section 6 sketches the implementation. Related and future works are discussed in the last section.