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Vol.26 No.4

Vol.26 No.4

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archive/21/3

Volume 21, No.3

Please, Mr President, Don’t Forget About The Working Man

Some of you have complained we could do more to help the working APL programmer. And you’re right.

Unless the Vector Working Group plans and solicits articles, Vector relies on what you choose to send us. And commercial programmers rarely see they have the time to write about what they’re up to. So hats off to the academics and hobbyists who have found or have just made time over the years to contribute to Vector. Please keep it up!

And we’re resolved to serve the working programmer better. This is the last issue to feature a Technical Section, and we’ve packed it with useful stuff. Kai Jäger writes his complete beginner’s guide to driving Excel from Dyalog APL. Excel is such an important part of our environment that we make no apology for publishing another article on interfacing it with APL. Even if you’ve never used OLE before, Kai’s step-by-step instructions will get you started with something that works; and through the miracle of Unicode you can copy his code straight off our website into a Dyalog APL session.

Similarly, the Web has become such an important medium for delivering computer services that we’re publishing in two parts Eric Lescasse’s guide to writing or porting APL2000 applications to Web Services.

When I started writing in APL, I loved how it liberated me from the yammering detail of FORTRAN. No more declaring variable types or array sizes; no more nannying loop conditions and counters. My new wings soon melted as I soared beneath the low sky of a 256Kb workspace and I had to learn how to live without WS FULL. But Moore’s Law worked its magic at last, making my time scarcer than silicon, and my everyday writing is guided by linguistic (or do I mean ‘literary’?) not engineering considerations. Mostly. But even everyday programming can still encounter the limits of the machines. Bill Rutiser explains in two articles how virtual memory works beneath the interpreter, and how to evaluate the impact of memory issues on your application.

MicroAPL has long emphasised cross-platform development in APL, and porting tools for migrating between interpreters. Adrian Smith offers his initial impressions of the built-in charting capability in APLX Version 3 (we’ll publish a full review in one of the next few issues), and Eke van Batenburg has reviewed the how various interpreters conform to the ISO standard for APL.

John Scholes’ modestly titled article argues the merits of the FP (Functional Programming) style of writing. This is illustrated in my case study of a program that interprets text files returned from mainframe queries, which parses about 700 queries a week at Britain’s largest insurer. The program has 25 executable lines; 24 of them simply define functions or constants.

Reading is as important to literacy as writing. Cliff Reiter uses the well-known Game of Life to compare the performance of different strategies in J, including Ewart Shaw’s ‘signature’ 1-line Game of Life program. Roger Hui explores in J a harder version of the Eight Queens problem. And Ian Clark considers in APL2000 an alternative to postal voting for electoral fraud.

Stephen Taylor


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