Author here. I wrote this because I thought APL deserved an up to date introductory text. It's basically the notes I kept when learning it myself. Stoked to see it on HN.
And in the end, I wonder if it is more readable than regex which is sometimes considered 'write-only', because reading it can be so time consuming. I know you wrote about the readability topic, but I don't mean 'can I read it', but rather 'How much effort takes it to read it'.
The second learning curve however is the much harder part, learning how to write APL 'idiomatically'. This is mostly true in any language though, especially one in a different paradigm.
The syntax is very simple, there's nothing scary about special characters if you can get over your fear of them, custom keyboard layout is absolutely not required (I've never used a custom layout for APL or Japanese or Cyrillic or Greek or any other non-latin characters that I type on a keyboard). Dialects are a thing but Dyalog is such an obvious choice if you want to learn APL that I wouldn't even worry about the rest. (K is worth looking into for its own sake but I don't consider it a dialect of APL; J might be a dialect worth exploring but so far it didn't impress me much and I found it much harder to read than APL).
One more thing: I find that reading APL is easier than writing APL.
so, while a considerably smaller language, it's like learning Chinese (for someone who uses a Western alphabet)?
7×3 ⍝ Dyadic × is multiplication
ׯ7 ⍝ Monadic × is 'direction', or signum (the sign, in our case). Thanks.
21
¯1
×-7
¯1
×7
1
×0
0See 5.3.5 for what that bit of code represents. The box is, in fact, being displayed correctly.
The xkcd "light saber" thing made lisp seem appealing to me a few years ago, but after a brief intro to the array languages, now I think they're much more deserving of that comparison.