Topics for a second course in APL

After students complete the introductory APL course, after they become comfortable with the concepts and after they use it regularly in their work, then the problem of enhancing skills must be addressed. This paper presents a syllabus of three lectures which comprise part of a second course in APL.

The purpose of Lecture I, MULTIDIMENSIONAL ARRAYS MADE EASY, is to help students deal with data stored in higher rank arrays. The idea of formulating such arrays frequently occurs naturally to users but they are reluctant to proceed because of the difficulty visualizing the arrangement. Six rules are presented to ease the way.

Lecture II, SPECIAL USES OF THE GRADE AND SCAN, alerts students to approaches and techniques which would not typically occur to them. Interesting applications of the scan operator yield utilities which produce expansion vectors and indexing vectors based on field lengths. The grade and double grade form the core of other utilities to merge data and to affect table lookup.

BUILDING BETTER USER/COMPUTER INTERFACES, Lecture III, is designed to facilitate delivering “closed” versions of “open” systems. Topics include a standard PROMPT utility, techniques in error trapping and a MENUDRIVEN MENUDRIVER.