Old Issues of APL News

I digitized these a long time ago, but I can't find any record that I posted about it! So here are some old issues of APL News, a newsletter about the computer language APL published from 1978 to 1982 by Ken Iverson. I contributed a little to it.

My Talk at the APL@50 Conference

Yesterday York University hosted a 1-day conference entitled "APL@50", to celebrate the 50th anniversary of the publication of Kenneth Iverson's book, A Programming Language. This book, and the subsequent implementation of APL, eventually won Iverson the Turing award in 1979.

Here are my slides for the talk.

I said a lot of things that were not on the slides. In particular: "More foolish things have been said about APL than any other programming language, and Edsger Dijkstra was one of the biggest offenders."

In addition to the talks, there were some really nice displays from the collection of the York University Computer Museum. For example there was an IBM 5100 APL machine (one that I spend several years programming as an undergraduate), and an MCM APL machine.

We also saw a short film by Catherine Lathwell, who is working on a full-fledged documentary about APL.

At a panel we were asked to summarize what APL meant to us. I said something like the following: APL taught us that a good notation is half the battle. Computing is ultimately about insight, and a system that encourages experimentation and variation is one that can be used to treat mathematics almost as if it were an experimental science.

Thanks to Zbigniew Stachniak and Catherine Lathwell for organizing this.

Remembering Gene McDonnell

I was very sad to learn this morning that my old friend and colleague, Gene McDonnell, died on August 17.

Gene was actively involved in the development and promotion of APL. He was one of the first people I met when I worked at the IBM Philadelphia Scientific Center, and he later hired me to work for I. P. Sharp in Palo Alto.

Gene had a wide variety of interests. He could talk knowledgeably about mathematics, science and literature, and he had a playful sense of humor. He wrote a beautiful paper entitled "Complex floor", which gave an entirely new way to generalize the familiar greatest integer function (or "floor") to the complex plane. As an undergraduate, I wrote my thesis on his extension, showing that you could use it to define continued fractions for complex numbers -- though there are still questions unresolved about that!

Gene and I wrote a paper together entitled "Extending APL to infinity", which suggested some ways of adapting the computer language APL to the extended real numbers. We also made a proposal to extend APL to infinite arrays, basically involving some lazy evaluation schemes. As far as I know, nobody ever implemented our ideas, although I still think it would be interesting.

Gene wrote a series of excellent columns for APL Quote-Quad (now sadly defunct) entitled "Recreational APL". For many of us, it was the first thing we turned to when the new issue arrived. I remember in particular one beautiful column about leap years that inspired a paper I wrote, "Pierce expansions and rules for the determination of leap years", in 1994.

Gene was intellectually active up to his last days. The most recent message I received from him was in April, where he proudly announced the publication of his new book, At Play With J, a compendium of his columns from Vector, the British APL magazine.

I'll remember Gene for his bright blue eyes, his warm and engaging smile, and his intellectual achievements. Farewell, old friend.

My Eulogy for Kenneth Iverson

Kenneth Iverson (1920-2004) was a computer scientist who invented the computer language APL. I was invited to speak at the Iverson memorial in Toronto on November 18 2004. I had lost my notes for my eulogy, but luckily Catherine Lathwell, who is working on a documentary about APL, has a copy of the videotape, and you can watch it here.

SIGAPL dissolved

A sad day for the APL community: SIGAPL, the ACM special interest group on APL, has been dissolved by the ACM SIG governing board.

I first learned APL in 1973 at the IBM Scientific Center in Philadelphia (long gone). At the insistence of my father, I had written to several large computing companies, asking for a summer job. Only IBM replied favorably, and I had a rather intimidating interview with Ken Iverson and Adin Falkoff in their offices on Market Street. To my delight, they hired me for a vague project about whether it was better to learn APL by reading other people's programs first, or writing one's own.

I remember going home with a copy of the APL\360 user's manual, which was initially very mysterious to me, and had an exotic smell like bacon. I had learned programming from Kemeny's book on BASIC, and APL was a revelation. I immediately took to the language and ended up spending the next few years of my life involved in APL in various ways: coding in APL for financial institutions, writing my own extended precision arithmetic package and selling it to IBM, etc. I was programming on IBM machines, using a printing terminal with an APL typeball.

I soon discovered the newsletter of SIGAPL, called "Quote-Quad". (The unusual name comes from the special APL symbol for character input, which was formed by typing a "quad" (shift-L) and overstriking it with a quote (shift-K).) At that time I eagerly awaited every issue, filled with incredible one-liners that accomplished results you would need hundreds of lines in BASIC to duplicate, puzzles like the self-replicating APL expression puzzle (type it in and you get exactly the same result back), and proposals to extend APL in bizarre and mind-expanding ways. It was really the golden age of APL.

It's clear that the passion and excitement about APL has decreased since then, although I still use APL on at least a weekly basis to do experimental mathematics: Dyalog APL on my Sun workstation, and APLX on my Macintosh. In many ways it is far superior to Maple and Mathematica, although the lack of easy availability of extended precision and symbolic arithmetic is a pain. I can code a quick-and-dirty solution to a problem faster in APL than I can in any other language. People who see it always stare open-mouthed: what is that? they say, and they want to borrow a manual.

The dissolution of SIGAPL is the passing of an age.