Array diagrams and the Nial approach
Fl. Schmidt, Michael A. Jenkins · ACM SIGAPL APL Quote Quad · 1982
The Nested Interactive Array Language, Nial, combines APL and LISP concepts and is based on the theory of nested rectangular arrays. Array theory provides a concise mathematical model of data capturing the essence of everyday data objects. Arrays are displayed by diagrams, which provide an easily comprehended way of communicating the rectangularity, nesting and content of arrays. A novel drawing technique is presented in which any array diagram can be drawn by combining only three kinds of primitive diagrams according to a few simple rules. The properties of the primitive diagrams and the consequences of the combinatorial rules are studied and exemplified.