Fun fact: All three of Go's creators have written APL interpreters, and Go's "iota" keyword is modeled after the corresponding APL operator.
>The author has never used APL. It's a chicken and egg problem. (...) All testing has been done with tryapl.org.
There are also a few free software implementations of APL most notably GNU APL. I have been sticking to that while learning APL. https://www.gnu.org/software/apl/
Dyalog is the only implementation that is robust and production ready that is still actively maintained. I would suggest learning with something other than the GNU implementation.
I did request a copy of Dyalog but they rejected my application (probably because I didn't add my address?). I don't have a lot of enthusiasm for learning using a proprietary implementation of a language anyway.
"The APL interpreter is an (almost) complete implementation of ISO standard 13751 aka. Programming Language APL, Extended."
I wish there were more languages like that.
"Ken suggested iota for the counter and, since all three of us (Ken, Robert, Rob) had implemented APL interpreters, it seemed a perfect thing to us." - Rob Pike
$, : The output field separator
$ perl -E 'my @data = (11,22,33); say 11,22,33; say "@data"; say @data; $,="|"; say 11,22,33; say "@data"; say @data;'
112233
11 22 33
112233
11|22|33
11 22 33
11|22|33
$" : Interpolated list separator
$ perl -E 'my @data = (11,22,33); say 11,22,33; say "@data"; say @data; $"="|"; say 11,22,33; say "@data"; say @data;'
112233
11 22 33
112233
112233
11|22|33
112233
Iota in APL is unary operator that generates a vector of consecutive integers starting at the origin up to and including its operand. Iota in Go is a predeclared identifier that can only be used in constant declarations wherein it auto-increments on every use. The resemblance is superficial at best.
> "Ken suggested iota for the counter and, since all three of us (Ken, Robert, Rob) had implemented APL interpreters, it seemed a perfect thing to us." - Rob Pike
Maybe we have just have a different view on what "modeled" means, or I am being too literal. To me, "modeling" implies that something is created with another thing in mind, adhering to the same principles. To relate that to the quote, I wouldn't call the process of coming up with a concept and only afterwards finding a name for it from some handwavely similar concept in another context modeling.
Still, I wouldn't call the resemblance superficial. "iota" in both languages refers to sequences of whole numbers. If "iota" in Go meant "the zero-value for an arbitrary object" or "the smallest non-zero float64," then the two would truly share only a name.
In the latter case, you can say that "A B C←⍳3" (at least in Dyalog) which is roughly equivalent to a Go constant assignment using iota if you squint a little and disregard the underlying procedure of creating and unpacking an array at run-time vs creating a compile-time constant. In the former case, I'm not aware of any analogue.