APL - A Programming Language

Today, I was reminded of one of the first programming languages I learned in the seventies: APL.

A Visma colleague from Riga, Latvia, pinged me this morning, saying, "Hey Jan, I've read somewhere that you know about APL. Would you be able to help us with a piece of software that is written in APL in the seventies? It is still operational and we have some questions about it." Wow... that's what you call legacy software!

But yes, I learned APL while studying mathematics in the seventies. I wrote my first lines of APL on a paper terminal.

APL, literally means 'A Programming Language'. The simplicity of this name is in stark contrast with how it looks, a bit like hieroglyphs1, and the keyboard is complicated too, with APL characters even on the side of some keys2.

Initially designed as a mathematical notation system around 1960, with a strong focus on working with multidimensional arrays, it soon turned out to be suitable as a programming language. One of the strength of it is its conciseness. I mean, the implementation of the Sieve of Eratosthenes to generate prime numbers can be programmed in a single line of APL, whereas in languages like C or Python, you would need dozens of lines. No wonder I soon became addicted to it. The result was that I wasn't found in the lecture halls anymore because I was playing around with APL at the university computer center.

Hence, my math study failed. But the knowledge of this programming language led to my first job as an APL programmer at the ABN Bank in Amsterdam. And that's how my career in IT began.