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Comment by AceJohnny2 | Hacker News Reader

> on his iPad (which is nicely suited to editing S-expressions)

How so? I'm curious.

There's a fun iPad app called Lisping that let's you play with different flavors of Lisp. Not really a programming environment, but it's sort of neat for trying out ideas.

How does that get around the iOS App store restriction on interpreted code?

Is that still a thing? I thought they relented?

I belive that restriction was lifted quite a while ago, like in 2010 or something. It didn't last long as game engines required the use of scripting languages for game logic, among other things. Apple simply had to cave in.

Excuse my ignorance, but what about the new situation that all apps MUST use ARC. Does that interfere with lets say embedded Lisps in Apps etc...

You don't have to use ARC. You can reference count manually if you like. What you can't do is use the old garbage collection (which was only ever available on OS X).

And in fact you _can_ still use the old garbage collection if you really want to; you just won't be able to submit new apps to the OS X app store.

Apple no longer allow use of Objective C garbage collection on the MacOS App Store (it was never supported on iOS). This doesn't effect third-party garbage collection and there's no requirement for third-party languages to use ARC (it wouldn't be practical for most of them, anyway, though there is an AOT-compiled Ruby that uses it).

Thank you!

I assume they got around that restriction by cunningly releasing it after that restriction was abandoned in 2010...

Ah, my inexperience with Apple's platforms is showing.

The restriction was reformulated to something like "you can't allow dynamic code loading over the net" or something. So as long as the app ships with the example snippets it runs and otherwise works only with user input, it should be politically correct.

Edit: reference: http://seattleclouds.com/ticketfiles/8665/ios_program_standa... 3.3.2 "An Application may not download or install executable code. Interpreted code may only be used in an Application if all scripts, code and interpreters are packaged in the Application and not downloaded." So in fact the Lisp app is also forbidden (but of course Apple is free to selectively enforce)

This seems to be done on a "spirit of the agreement" basis; they're okay with the various python REPL languages even though you can do things like eval(urlopen("http://bla.com/some_python.py").read()), for instance.

Ah, I didn't even think that far, I stopped at any REPL being a violation since it's running code which was not packaged with the app.

App Store link, for anyone that's interested: https://itunes.apple.com/gb/app/lisping/id512138518?mt=8

I think it might make more sense to say that S-expressions are less of a pain to edit on touch devices than most other expressions, as people have made nice tools for them.

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