Vector vol. 23 Nos. 1&2 Contents Editorial Stephen Taylor 2 Sustaining Members News

Contents

BAA AGM 2006 Anthony Camacho 7

The Elsinore Songsheet 9

APL’s 40th Birthday Party in Stuttgart Adrian Smith 12

Building OO Applications Stephen Taylor &
in Dyalog Version 11 Gilgamesh Athoraya 17

The APL Wiki Kai Jäger 19

BAA AGM 2007 Anthony Camacho 24

Kx Conference 2007 Stephen Taylor 25

Can One be Fit on a Starvation Diet? Sylvia Camacho 26

DISCOVER

Review: “System Building with APL+Win” Ian Clark 61

Design Decisions in APLX64 Richard Nabavi 68

LEARN

Building C# COM DLLs for APL Ajay Askoolum 85

Zipping and Unzipping Files in APL+Win Ajay Askoolum 97

Analysing CONTINUE workspaces Ray Cannon 101

New Tricks for Old Dogs:
Making Sense of Classes and Namespaces Adrian Smith 110

In Session: The Ruler’s Edge Stephen Taylor 115

PROFIT

3-D Cellular Automata and the Game of Life Timothy K. Zirkel 123

Cumulative Normal Distributions Ralph Selfridge 135

Digitalising the Vector Archive Ian Clark 139

Editorial: A Lot Happening

A lot to report on in this issue. That’s partly an artefact of how far we again dropped behind our publication schedule, so let’s start by looking at that.

For many years production of Vector would have been beyond the means of the BAA were it not for the skills of Adrian Smith at Causeway Ltd. In the course of this work he has designed and produced the APL385 Unicode font used both for Vector and the APL Wiki. (See Kai’s article.) But even minor interruptions to Adrian’s availability can disrupt regular production of Vector.

Happily, the spread of Unicode browsers enables much simpler typesetting solutions. So we’ve begun a project to simplify the markup and composition work. We have for some time preferred to receive articles as text files or HTML documents. As part of this project we’ll produce a simple guide for authors to marking up articles for Vector, either as HTML or as XML, using just a text editor. (We know this won’t work for everything we publish, so we’ll continue to negotiate format and content with authors as necessary.) This will reduce the work required to prepare an article for publication, and opens the way to publishing – eventually – articles promptly online before we collect them in a printed volume.

BAA is following Dyalog’s lead to Lulu.com’s print-on-demand service. We plan to use this to make printed or PDF back issues of Vector available on demand, and to publish a series of Vector Books, starting this autumn.

But there is also much to report. Kx Systems goes from strength to strength. Its first residential user conference is beginning in Ireland as we go to press. Much welcome news from Dyalog Ltd, which has moved into new offices, expanded to 13 staff, and has acquired Causeway’s admired line of software tools. Morten Kromberg has also been spotted playing with an experimental Dyalog interpreter with native Unicode character strings, and demonstrating that while the five thousand Chinese characters in the Unicode set might look alike under Western eyes, their shape and their nub’s shape are in fact the same.

Kai Jäger has, with help from Chris Burke at Jsoftware, established the APL Wiki, modelled after the successful J Wiki. It’s hard to overstate the potential importance of this. The difficulty of reading and writing the traditional APLs on ordinary PCs and on the Web has been widely blamed for their fall from favour.

Now, and for the first time, APL programmers have the prospect of sharing code over Web pages, cutting, pasting and typing their code. (If you are using a Unicode-enabled APL like APLX or Dyalog, you can also cut and paste between your session and the APL Wiki.) Hats off to Kai for envisaging this, and for contributing the time to make it all function. Making it useful is a job for the rest of us!

More crossover action from the Kx Systems user conference in Ennis, Ireland (May 2007). Arthur Whitney’s Q programming language can be thought of as an APL savagely hacked for raw speed. In the course of developing it, Whitney excludes anything and everything that might compromise that goal. Once a Q program has worked its magic with billion-row tables, it leaves its author reaching for richer tools for presenting the results. Morten Kromberg of Dyalog showed how a full-featured APL could take over the running without losing the productivity of Q’s array paradigm. Expect to see more exploration of the APL-Q partnership.

I’m sorry to report that Eugene McDonnell plans to send us no more “At Play With J” articles. We’ve had 38 of these over the years; Eugene tells us each one took about a month to write. It’s the end of an era. To mark our appreciation of this work, the BAA will collect and publish it in book form this year.

This issue contains a substantial introduction to APL by Bernard Legrand, translated from the French, a labour of love by Sylvia Camacho. Richard Nabavi discusses the design decisions behind the 64-bit version of APLX.

Much practical help in APL+Win here from Ajay Askoolum. Ian Clark reviews Ajay’s new book, and we add two articles by Ajay, on writing C# COM DLLs, and on zipping and unzipping files in APL. Klaus Christiansen offers his APL wrapper for the widely-used Developers Image Library, and Ray Cannon, master of crash recovery, writes about handling and analysing CONTINUE workspaces. Adrian Smith offers his own take on classes in Dyalog 11.

This issue kicks off a new column In Session, successor to the long-running Hackers’ Corner. We’re looking for fragments from your session logs when you’ve done something elegant, impressive, useful or just curious – perhaps not worth working up into an article, but nonetheless worth sharing. Show us your moves!

As always, we have articles by people using the APLs to get results in their own fields. Sylvia Camacho adds another article to our series on the Monty Hall problem. Timothy Zirkel plays the Game of Life in 3-D, and Ralph Selfridge considers different ways to write the Black-Scholes algorithm. And Ian Clark describes his agile and innovative approach to digitalising the Vector archive.