Why APL Is Still Cool

I've always found APL really intriguing. A professor of mine told me about how one of his students used to be able to solve ACM competition problems incredibly fast by simply not having to type very much. There are some insane videos on youtube of people solving problems in APL [1].

But, you know - it's write once, read.. never again.

[1] http://www.youtube.com/watch?v=a9xAKttWgP4

Check out J. There are a few inconsistencies in APL that are remedied in J, though you lose out on the "cool" non-ASCII operators.

http://jsoftware.com/

I learned APL in college and used it professionally for about eight years. I really enjoyed the language. Once you know it well enough it creates a very interesting flow condition. You are able to focus on the problem rather than the mechanics of solving it. It's hard to describe but you definitely feel the difference when going from APL to something like C, Forth or Lisp.

One of the huge problems with APL back then was that workspaces (the memory and resource sandbox your work is constrained to) were limited in size. The other was the trouble you had to go through in the early days to be able to see and print the character set. On early IBM PC versions you had to change the character generator ROM. You also had to buy very specific printers for which you could buy APL print heads (for example, IBM Selectric).

Today these issues are gone and workspaces are large enough to tackle the vast majority of problems.

There is, however, in my opinion, a serious problem with APL today: It is too expensive.

Yes, there are low cost or even free APL's, but the ones you want will run you $1,000 to $2,000 per seat. That's ridiculous. If there's a language that would have benefited from FOSS, this is it. I strongly believe that APL adoption would be far wider today if it had a strong FOSS offering.

The other issue is that, probably because it didn't go FOSS, the language didn't evolve into OO. I think it needs to. It also needs a few additional mutations to make it easier to work with and deploy. APL for the web, as a wild thought, could be a very interesting idea. The compression of code would be magnificent to see.

I haven't used APL in quite some time but would jump on it if it made sense. Back in the day I used APL for projects ranging from robotics, to business databases, DNA sequencing and astronomical calculations. It was fun.

To me the biggest lesson from APL is to always try to manipulate the largest data structure you can your hands on. For example, don't think about for-loops, think about 'map'. When you can do that, life is good.

The limitations of the language that I saw (in the mid 90s) were around interoperability. Devs saw it as esoteric and steered toward something more 'marketable' like C++ and later Java. The extensive use of memory mapped files for persistence made it 'viral' in terms of building apps to access data. The language (or more likely the library support) was great for pricing algorithms but not so great for business applications filled with corner cases. As I recall these were reasons it was phased out at Morgan Stanley.

another link if the original doesn't work for you: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.94.4...