Practical uses of operators in Sharp APL/HP

ABSTRACT

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.

REFERENCES

• 1: Robert Hodgkinson, APL procedures (user defined operators, functions and token strings), Proceedings of the international conference on APL, p.179-186, July 07-11, 1986, Mancheester, United Kingdom
• 2: Edward V. Eusebi, Operators for program control, Proceedings of the international conference on APL: APL and the future, p.181-189, May 12-16, 1985, Seattle, Washington, United States
• 3: Edward V. Eusebi, Operators for recursion, Proceedings of the international conference on APL: APL and the future, p.190-194, May 12-16, 1985, Seattle, Washington, United States
• 4: Kenneth E. Iverson, The role of operators in APL, Proceedings of the international conference on APL: part 1, p.128-133, May 30-June 01, 1979, New York, New York, United States
• 5: K. E lverson, "Operators and Functions", Research Report GRC7091, IBM Corp, 1978.
• 6: K. E. Iverson, "Rationalised APL", I. P. Sharp Associates Research Report #l, April 1983.
• 7: Carl M. Cheney, "APL*PLUS Nested Arrays System", March 1981.
• 8: Kenneth E. Iverson , Arthur T. Whitney, Practical uses of a model of APL, Proceedings of the international conference on APL, p.140-145, July 26-30, 1982, Heidelberg, Germany
• 9: Jean-Jacques Girardot, The APL 90 project: new directions in APL interpreters technology, Proceedings of the international conference on APL: APL and the future, p.12-18, May 12-16, 1985, Seattle, Washington, United States
• 10: Alan Graham, Idioms and problem solving techniques in APL2, Proceedings of the international conference on APL, p.172-178, July 07-11, 1986, Mancheester, United Kingdom
• 11: K.E. Iverson, "Applied mathematics for programmers", I. P. Sharp Associates, Draft of 28 November, 1984.
• 12: Robert Bernecky, Function arrays, Proceedings of the international conference on APL, p.53-56, June 11-15, 1984, Finland

INDEX TERMS

Classification:
  D. Software
  D.3 PROGRAMMING LANGUAGES
      D.3.2 Language Classifications

          Nouns: APL
      D.3.3 Language Constructs and Features
          Subjects: Procedures, functions, and subroutines

General Terms:
Design, Languages