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APL is Easy!/APL2 at a Glance

Reviewed by Bill Ross

Vector 5:3, page 51

reviews education

Transcribed from the printed issue; not yet reviewed. Read it in the PDF of the issue, page 51

APL Is Easy! by Jerry R Turner (STSC,Inc.)

APL2 at a Glance by James A Brown, Sandra Pakin and Raymond P Polivka

About the Reviewer

Bill Ross teaches Modern Languages at Ampleforth College (one of the UK's major independent schools). His interest in APL has come both from the academic angle (a love of Russian and Chinese helps), and from an appreciation of its usefulness in simple tasks like working out end of term averages and grades.

Summary

The authors of both the above texts - all of whom are experienced APL educators - have given us two very useful primers for beginners.

APL is Easy!

As a "natural" linguist and non-APL speaker, my curiosity about the syntax and semantics of the language has rapidly been satisfied by APL Is Easy! The author makes no bones about the modest scope of his manual, which admirably achieves its aim of getting the reader to 'learn the language easily' and of teaching him some useful things to do with what he learns. The exposition of the text is a model of clarity (as is the page layout) and the copious examples and exercises are conceived in such a way that the reader gains confidence in his ability to solve problems using APL and gains insights into some useful everyday applications. Solutions are provided at the back, making the text eminently suitable for self-study. The author views his book as an introduction to a more substantial treatment of APL, such as Gilman and Rose. Having embarked on the quest for APL by using rather more arcane materials of dubious pedagogical value, I was relieved and overjoyed to discover a book which actually sets out to explain and teach the language to the non-initiate.

The 10 chapters are:

  1. What is a Program
  2. Simple Arithmetic, Error Correction, and Data Storage
  3. Character Data, More Arithmetic and More APL Functions
  4. Selecting and Analyzing Data
  5. Writing Programs in APL
  6. Formatting
  7. Storage Facilities: Workspaces
  8. Storage Facilities: Files
  9. APL Programming Techniques
  10. Exploring APL

The book concludes with solutions to the exercises, 3 appendices, a glossary and an index.

At £15 it is hardly a "steal" at the price, but for those seeking to learn the language autonomously, it is well worth the money.

APL Is Easy!
by Jerry R Turner (STSC,Inc.)
Paperback, 180pp text plus 66pp appendices and index
Published by John Wiley & Sons, Inc., New York, 1987
Price £15

APL2 at a Glance

APL2 at a Glance is an introduction to the programming language APL2, the PC version of which has recently been released in this country by IBM. APL2 is more versatile than APL and opens up a wealth of new programming paradigms that do not exist in APL. This text is also aimed at the reader without any prior knowledge of APL, though its authors consider that it will also be of interest to fluent speakers of APL 'because of its emphasis on the APL2 data structures and the style of programming brought about by its new functions and operators.'

Once again the exposition is gradual and clear, though the layout is rather less pleasing than the Turner text. (What a shame that the laminated paper cover of the book will not lie flat! - a bibliophile's quibble, albeit.) In common with the Turner text, each chapter includes a wealth of examples which demonstrate the notions discussed and the exercises help one understand the capabilities and practical applications of APL2. Unfortunately I was unable to work through all of the exercises on my computer , since I do not yet possess a copy of APL2. The exercises require the student to evaluate expressions or to work problems involving the creation of expressions and functions.

The fact that this expository text is so highly readable and accessible to the beginner is, no doubt, the result of the authors' close acquaintance with the implementation and teaching of the 'old' APL as well as APL2, both within and without the IBM organisation. The authors are to be congratulated for this considerable pedagogical achievement. The work is suitable for either independent study or classroom use.

APL2 at a Glance contains 8 chapters that present the basic features:

  1. Working with APL2
  2. Working with Vectors
  3. Working with Programs
  4. Working in the APL2 Environment
  5. Working with Arrays
  6. Working with Data
  7. Working with Program Control
  8. Working with Applications

APL2 at a Glance has several appendices - some highly entertaining -, a glossary, a bibliography containing selected titles on APL" and works cited in the text and an index. I found appendix E, which gives the nomenclature for the APL2 character set particularly helpful.

APL2 at a Glance
by James A Brown, Sandra Pakin and Raymond P Polivka
Paperback, 373pp text plus 88pp appendices, index, etc.
Published by Prentice Hall, Englewood Cliffs, New Jersey 07632
Price £21