Practical uses of operators in Sharp APL/HP

• Authors: Robert Hodgkinson
• Venue: APL '87 Proceedings of the international conference on APL: APL in transition
• Year: 1987

At APL86 in Manchester, the language features of SHARP APL/HP on a Hewlett Packard range of minicomputers were introduced in a paper written by this author, entitled 'APL PROCEDURES (USER DEFINED OPERATORS, FUNCTIONS AND TOKEN STRINGS)'. This is the first of several papers which have been planned to supplement this introductory work. The models of several new and existing operators are described in detail, all of which may be directly executed in SHARP APL/HP. The models take advantage of various features of SHARP APL/HP including extended assignment and procedure arrays [1] (often referred to as function arrays in their most common form). The paper will pursue a comparison of the less general implementation of operators in APL2, with special reference to Ed Eusebi's pioneering work in the field of 'Operators for Program Control and Recursion' [2 3], wherein an alternative definition for several of these operators will be proposed. The paper will then proceed to describe 'Operators applying to Enclosed Arrays' (for example a Pervasive Operator) and various 'Mathematical Operators' (instances of which are the Power and Transitive Closure operators), always highlighting these models with examples of their practical application.