OUR EXPERT
Mike Bedford might not use it in anger, but he’s been fascinated by APL’s quirkiness since he first saw how it could generate prime numbers in just 20 characters.
The classic IBM 5110 luggable, as we discovered in LXF291, ran APL, which stands for A Programming Language, yes really. Despite APL – according to the TIOBE index of the popularity of programming languages – languishing somewhere between the 50th and 100th positions, we were surprised to find that APL still has an enthusiastic following among enthusiasts and for developing commercial applications.
As always, the unexpected is the trigger for articles, and we’re delving into classic programming languages and why some coders choose APL over today’s latest and greatest languages, and what types of application benefit from its different approach to problem solving.
APL overview
Before starting to look at how and why APL is used today, we ought to paint a picture of it. Common descriptions range from unusual to downright bizarre. In fact, a professor of computer science at an American university is on record as saying that “APL is a language designed by a mad-man”. Part of the reason that APL is considered strange is its use of special symbols, instead of keywords, for many of its functions. We also have to say that it is terse in the extreme, as you can see from the following hieroglyphics: , which is a variant of the commonly cited code for displaying all prime numbers up to a maximum of X. Part of the reason that APL code is so concise is that, although some newer variants
