With the Dyalog APL book going 800 pages I hope more won't be required to get feel of the language ;)

I tried meaning of life from FinnAplIdioms on TIO. Sadly it didn't produce any output...

I just looked at the meaning of life. That's unlikely to work with many "hosted" APLs because of the use of eval, which is a security concern in an online REPL.

However, if you remove the execute you can still get a string version:

      ⊖⍕⊃⊂|⌊-*+○⌈×÷!⌽⍉⌹~⍴⍋⍒,⍟?⍳0

42

You can paste this into the REPL at TryAPL.org.

Well, it seemed interesting and I suspected it would result in 42, however else it would do its work :) Perhaps that's one way t frame the Question.

What's really interesting about the above is that it is "seeded" with a random number. :-)

Remember that the FinnAPL library expects that you know your APL environment and are able to adapt the idioms to suit.

You should also consider "Notation as a Tool of Thought" by Kenneth Iverson (his Turing Award lecture) to be required reading.

I think it's this: http://www.jsoftware.com/papers/tot.htm

I thought I had read it at some point, but now it doesn't ring a bell. Well, it's on the list now. It starts with Babbage quote and uses phrase "tool of thought" which coincides early computer history books I've been reading.

Yes, that would be the one.

If it's a comfort at least 200 of those pages are going over libraries that are shipped with dyalog but have nothing to do with the actual language.