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Comment by kasbah | Hacker News Reader

Rob Pike also implemented an APL-like big number calculator in Go more recently: https://github.com/robpike/ivy

>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/

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I've personally found GNU APL to be a bit flimsy, and not some of the design choices they made in it to be a bit odd. It also deviates from the ISO standard, if that matters to you.

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 am learning using the book "APL with a Mathematical Accent" and so far all the examples work fine (I am on chapter 3). I'll probably switch to learning J if I start running into problems. It says on the GNU page "implementation of ISO standard 13751" so if it's not standards compliant it should likely be filed as a bug.

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.

I'm not sure where you are seeing that, on the GNU page I'm looking at[0] they are very clear that they are not following the complete standard.

"The APL interpreter is an (almost) complete implementation of ISO standard 13751 aka. Programming Language APL, Extended."

[0] https://www.gnu.org/software/apl/

That reads to me like they are aiming for standard compliance but the implementation is still incomplete, which is quite different from deliberate deviation from the standard.

Dyalog also deviates from the ISO standard, adding things from J like hooks and forks. IIRC, GNU APL's deviations are to bring it closer to IBM APL2, but it's been a while since I cared about any of this.

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