[4thaccount]

Well there are books like "Mastering Dyalog APL", but they don't help you think in the language. There is the "Finnish APL Idioms" book which helps a bit. APL and J certainly have libraries, but a lot of functions and libraries that are builtin to most languages are omitted from APL as you can replicate with 3 characters. That's where knowing idioms helps. I am just a novice, but really enjoy writing APL & J. Aaron Hsu has been on a couple of APL related posts on HN that I have linked to multiple times. He is a scheme guru that switched to APL a few years back and wrote the Co-Dfns parallel GPU compiler for Dyalog APL. He has some enlightening talks on YouTube as well. I mention him here as his APL code is extremely terse and similar to Whitney's C, and he did an excellent job defending it in the HN post which changed the way I look at code. Second, as a University TA, he's taught multiple courses on APL as a first programming language and has talked about writing a book that tries to teach how to THINK in APL and not just this is how you transpose the matrix using this symbol...etc. My problem is that I know what the symbols do, but don't know how to switch from imperative/OO thinking to how to think in terms of array primitives (inverse, transpose, sort, outer product...etc).

[avmich]

"J for C programmers" is, in my opinion, an excellent resource for how to think in array-oriented style. http://www.jsoftware.com/help/jforc/contents.htm

[4thaccount]

I've flipped through it before, but didn't remember it being very enlightening (note that I didn't read the full thing and do all the excercises). I'll have to give it another shot. Thanks for the tip!