[leephillips]

APL’s verbs are geometrically suggestive. They are little pictures that represent what they do, and how they are related to each other. For example, ⌽ reverses an array along its last axis; you can see the array flipping around the vertical line. And you will know what ⍉ does without looking it up, I bet. These symbols are so well designed that you don’t have to memorize much, because they document themselves.

[3wayMerger]

Couldn't the same be said of J? If APL's powerful notation comes from not having to memorize much and being a good visual representation of what the verb does, doesn't J's usage of alphabetical characters achieve something similar albeit a bit worse? For example "i." for index and related functions. Since the letter 'i' is usually used for indexing, one could assume that "i." is something related to indexing. Does the usage of alphabetical characters weaken the notation so much that it could be considered an abomination?

If there was another language that was a copy of APL but with new non-alphabetical symbols that were less suggestive than the original APL symbols, would that language be considered to have a less powerful notation? If so, how much weaker would it be considered? What would the symbols of a language that is APL-like and uses non-alphabetical characters, but would still be considered an abomination look like? Would that language be considered to have a more powerful notation than J?

This might be a bit of a stretch but I'd like to use the symbols on a media player as an analogy. The symbols on a media player (play, pause, resume, seek back, seek forward) could be compared to APL's symbols. Then, for the J version of the media player, rather than the symbols, there could be "Pl", "Pa", "Re", "SB", "SF" or something of the sort. I would say that the APL's symbols do look nicer, but I don't think J's usage of alphabetical characters should be considered an abomination. If so, wouldn't all text GUI's (e.g. command line managers such as nnn or MidnightCommander) be considered an abomination compared to a regular GUI version?

Maybe I'm not looking at the right thing here but APL's and J's notation seem to be similar. One does look better than the other, but both seem to serve the same purpose.

[leephillips]

I’ve only glanced at J and never used it, so I don’t have any strong opinions about it. But APL just has that extra magic that J seems to lack. Notation does matter. It could be that I’m partially sentimental, as it’s the first programming language that I learned.

[robomartin]

> Maybe I'm not looking at the right thing here but APL's and J's notation seem to be similar. One does look better than the other, but both seem to serve the same purpose.

Not sure if it is possible to understand this without having the context of being well versed in another means of communication that uses specialized notation. Musical notation being an easy example of this. Mathematics could be another. And, of course, languages that don't use the latin alphabet. Outside of APL, I happen to be fluent at musical notation and one non-ASCII spoken language, as well as having the mathematical background.

The closest I can come to explaining what happened with J is that they did their best to convert every APL symbol into an equivalent combination of ASCII characters. Here's the key:

They did NOT do this because Iverson thought this was a better path forward. He did not abandon thirty years of history creating and promoting notation because mashing ASCII characters together was a better idea. He did this because computers of the day made rendering non-ASCII characters a pain in the ass. This got in the way of both commercial and open adoption of the language. He likely genuinely thought the transliteration would bring array programming concepts to the masses. It did not.

In the grand context of computing, J is a failure and APL suffered greatly when its creator and primary evangelist abandoned it.

Imagine a world where people are writing perfectly legible code in C, Basic, Pascal, etc. Now imagine someone proposing the use of seemingly random arrangements of ASCII characters instead of those languages. It's like telling everyone: Stop programming in these languages! We are all going to program in something that looks like regex!

Well, the rest is history. The proof is in the fact that APL is but a curiosity and J isn't a commercially viable tool. Yes, they both exist in corner-case applications or legacy use. Nobody in their right mind would use either of them for anything other than trivial personal or academic applications. That's coming from someone who used APL professionally for ten years and even envisioned a future creating hardware-accelerated APL computing systems at some point. It's computer science history now.

I still think it should be taught (along with FORTH and LISP) as there's value in understanding a different way of thinking about solving problems computationally.

As an extension of this, part of me still thinks that the future of computing might require the development of specialized notation. For some reason I tend to think that working at a higher level (think real AI) almost requires us to be able to move away (or augment) text-based programming with something that allows us to express ideas and think at a different level.

[3wayMerger]

Thanks for taking the time to reply. I think I'm beginning to understand but am not quite sure.

While I wouldn't consider myself fluent in any of the following, I do know how to read musical notation (from middle school/high school band) and I can read/write/speak a non-ASCII language (Korean). So I am somewhat familiar with non-ASCII notation.

> The closest I can come to explaining what happened with J is that they did their best to convert every APL symbol into an equivalent combination of ASCII characters.

This is the statement I keep on getting stuck on. From what I have read, besides the symbols being converted to ASCII characters, APL and J are generally the same. Both work on arrays, both are parsed right to left, etc. It seems like the only major change is that the symbols got converted to ASCII characters that are at a maximum 2 characters long. If this is the case, what would you say about the J language's notation if the authors one day decided to change all the symbols to non-ASCII characters? Everything else would stay the same, such as what the symbols do and how much space the symbols takes up (max 2 characters). If the J language were to change only its symbols and nothing else, would its notation be considered to be on par with APL's?

As you mentioned, my lack of proficiency in other specialized notation might be preventing me from understanding the issue. That said, your last set of comments strikes a chord with me and I do think I kind of understand. As you mentioned previously, notation is "a powerful tool of both expression and thought." The usage of specialized notations allows one to express their thoughts and ideas in a way that normal writing can't. But I guess this is where being well versed in the subject matter comes into play, since after all it is a "specialized" notation. It would be difficult for someone who doesn't have a strong background in the subject matter to take advantage of the specialized notation.

To me, with my limited knowledge and experience, J vs APL appears to be a symbol (graphical) design comparison rather than a notation design comparison. And as someone who doesn't have a strong mathematical background, both APL's and J's symbols conveyed nothing to me when I first saw them. Changing the symbols to non-ASCII or ASCII has no effect on me besides figuring out how I would input the non-ASCII characters. But I suppose that to you, a change in the symbols isn't something so superficial. The way I understand APL vs J now is that for those who are experienced in APL, the changing of the non-ASCII symbols to ASCII characters, simply for the purpose of not having go through the trouble of inputting non-ASCII characters, "broke" the notation.