[liveranga]

Having J on the phone in your pocket is great.

And lots of the "labs" (interactive tutorials) are built in too: 3 dots -> Help -> Labs..

Edit: I should also have mentioned that Termux on android can build ngn-k, goal and a bunch of other open source array languages too.

There's also Rob Pike's Ivy language for Android too.

[ofalkaed]

For android and apl we also have dzaima's AndroidIDE which is the best android array implementation that I have found.

https://github.com/dzaima/APL/tree/master/AndroidIDE