Back in the mid 80's (I don't remember exactly) dealing with APL on IBM PC's was not easy. You really had to want to run APL.
For example, we had to hack the equivalent of today's graphics card to replace the character ROM with one programmed to display APL characters. The more advanced modification allowed you to throw a mechanical switch and go between APL and non-APL characters.
Printing APL characters required using very specific printers and changing the print wheel or ball (IBM printers) with versions having APL characters.
Again, you really had to want to run APL to endure this. And, that, of course, affected adoption. You couldn't run APL on any random IBM PC or clone on a desk.
So, Iverson, despite identifying notation as one of the more powerful features of APL, ends-up "going commercial" by transliterating APL symbols into combinations of ASCII characters. Now you could run something that behaved like APL on any computer. And, of course, it was a complete abomination. Terrible thing.
I think I can say the APL community rejected J almost universally. Doing this was a terrible idea. And a short-sighted one at that. It wasn't long til all computers had the ability to display expanded character sets and eventually full graphical canvases where anything was possible.
J was a commercial reaction to a hardware problem that evaporated very quickly. J was not a commercial success for reasons obvious to those of us who used APL professionally every day for years: It was a hot mess and almost diametrically opposed to what made APL so incredible to use in solving problems through computing.
I would stay far away from J. As brilliant as Iverson had to be to create APL when he did, J, as far as I am concerned, was an almost unforgivable mistake.
You mentioned in another comment that if APL is to go anywhere, that it needs to be open sourced. Unfortunately, the cost of Dyalog and the fact that it is closed source are the main reasons why I've ended up using J.
I appreciate that Dyalog is free for non-commercial use, but I think that part of what makes a programming language successful is if people can start using it in small ways to make their work better. For instance, at my previous job we started using Go for small things and it eventually took on a larger role once we saw how well it worked out in practice. Had we needed to pay to use Go for those small things, we never would have even tried it in the first place. I realize that the Dyalog company needs to actually make money somehow, but I wonder if they are aware of this problem. I did email Dyalog to see if using Dyalog for my work at a non-profit constituted commercial use, but they said that it did. :(
Edit: The reason why I haven't used GNU APL is because it seems like getting it to work under Windows will be difficult, and my work is unfortunately a Windows environment. Maybe I should give it a shot anyway.
