I've heard some conflicting things about the acceptability of scripting languages (e.g., Lua) in apps for the App Store. I'd like to hear from anyone who understands the policy regarding apps which contain some level of programmability, or someone who has had experience submitting such an app for approval.
For instance, suppose I want to develop a statistical package of some sort. It might provide the user with an application-specific language to code scripts that would manipulate data by calling built-in statistical functions.
If this scripting facility has no access to any entities outside of the application's sandbox, is it likely to present a hurdle to App Store acceptance?
Yes.
Using Javascript code run inside a UIWebView is an explicitly allowed scripting methodology. See PhoneGap for one example usage.
Other scripting languages may be acceptable if they do not run any downloaded code or compile any executable code (even JIT). This is standard methodology for many 3D game engines. (Apple's SDK agreement was changed to allow this circa September 2010.)
Added comments:
Other examples: There are at least 5 Basic interpreters and several programmable calculators currently in the iOS App Store. Perhaps interpreters for Scheme, Ruby and Python as well.
Unknown: If you were to develop an interpreter in Javascript for a statistical language, could that Javascript in a UIWebView download and interpret source code in that application specific statistical language?
If this scripting facility has no access to any entities outside of the application's sandbox [. . .]
Yes, that should be fine. The latest App Store guidelines explicitly permit interpreted code provided that it is not updated remotely.
Related
I want to make a Fortran editor in iPhone. User can code with Fortran in an iOS app and are also able to run that code on iPhone.
Can anyone guide me with correct approach?
I had a look to the gFortran, but its not available for ARM architecture.
Thankyou..
Apple doesn't allow for compilers or interpreters on the iPhone, but there technically isn't any reason you can't setup a server based compiler, that also allows users to run their compiled apps. In fact, there are multiple sites that already do just this, but it wouldnt be a good idea to write an app that points to their site or uses their services; you would need to setup your own service.
Not insurmountable, but I would move onto other app ideas.
Given Apple's snarly attitude about language interpreters running under iOS you're better off coding this as service that runs on a remote server, maybe with the editing part on the phone or tablet.
Updating this old thread for the sake of current and future searches:
Apple has changed their attitude over the past year or so. There are currently many interpreters available for iOS, including for Lua (https://itunes.apple.com/us/app/iluabox/id398073834?mt=8) and several for Python (https://itunes.apple.com/us/app/python-2.7-for-ios/id485729872?mt=8, http://itunes.com/apps/pythonmath).
One significant remaining restriction is that these apps may not load scripts from outside the app, for example, from Dropbox or iTunes file sharing. (This is part of Apple's efforts -- along with code signing and 100% app review -- to minimize malware.) Such apps are allowed to have an editor that allows the user to copy and paste code into the editor from outside the app.
As far as I know, there aren't any apps for compiled languages such as FORTRAN.
Meanwhile, FORTRAN compiler is available for iOS only as a jailbroken application.
[Disclaimer: I am the author of Python Math. Apple removed it from the store for a short time until I removed iTunes file sharing and "Open In..." capability. I then added a script editor.]
I have an application to develop but the problem is that is must download part of behavior as a list of instructions from a server.
Ideally it will download scripting code and execute it. The question is if there are any libraries to make it? For example, I have python script and I want to to execute it on device...
Any options?
thank you
Lua is very popular for games. You can embed Python, too. Apple won't enforce the "Objective-C only" clause unless you make it obvious that you use Python to script behavior. Do you think all the games on the store are scripted in Objective-C? No way. Just don't make your transgressions obvious and you'll be fine.
For security reasons, the app store does not allow apps containing programming languages capable of executing arbitrary code on the phone, so your app's market would be limited to users willing to jailbreak their phones to circumvent this restriction.
You could, depending on what you want to do, look at using the browser's JavaScript.
It is said here:
http://fourdman.blogspot.com/2009/06/cocolua-lua-objective-c.html
Lua is a very lightweight (but powerful) language which depends on C only. You don't need to pull many N-megabyte frameworks and libraries. Lua was created as an embeddable language: you add its interpreter's source code to your project and use is programmatically. Apart of many other things that means that you can use Lua even on the iPhone and no one will ever notice that.
As far as I understand new Rebol 3 core version (rebol view can't be used but cocoa gui framework) will have the capability to be an embedded scripting engine. Does this mean that it could be embedded like LUA in Corona SDK as a scripting language for the iPhone or maybe also Android ?
Rebol core is much less than 1 mo Lua I don't know I'm just downloading it.
Apple allows embedded scripting languages in iOS apps (there are even Basic interpreters in the App store), but does not allow any capability for an app to download new code or scripts which that scripting language can run. All scripts have to be built-in to the submitted app.
This was a change to their developer agreement about late-Q3 2010.
When porting a scripting language, you also have to make sure the language's run time does not reach outside the iOS process, file directory, and IO sandbox, but only uses documented Cocoa Touch APIs for IO and UI (e.g. no stdin, etc.)
Apple doesn't want anyone to create iPhone apps outside of the Xcode/Objective-C environment. How can they actually enforce this?
If the non Xcode IDE, for example Unity, compiles to an iPhone executable, how will Apple know which dev environment you used to create the app? Can they have Xcode compile some sort of signature into the executable that no one knows about?
For tools such as unity, corona, flash, and other platforms used to 'generate' iphone apps, Apple may be able to 'decompile' and examine your app (look at patterns of generated functions, etc). From this, they might be able to guess that your app was generated with such a tool.
In the limit, this is impossible. Consider the following: I write some script code to generate a bunch of objective-c code. Then I manually import the objective-c files into xcode and build the app. How would apple be able to distinguish the script-generated code from human-written code? Maybe I just tend to write code that happens to look machine-generated. There's no way for apple to determine whether the code was "originally written in objective-c, c, c++ or javascript" or not, yet this would still, technically, violate the agreement. That's why the 3.3.1 part of the agreement is nonsense.
Most automated systems do things a particular way, which isn't hard to detect. If you've ever looked at the PHP or JavaScript code Adobe Dreamweaver generates, for example, you know how easy it is to find stuff like this.
Apple is doing this to prevent people from using Adobe's Flash development framework. It should also be noted that Apple's decision to limit Application Frameworks like this is causing the DOJ/FTC or some government agency to start an informal inquiry into monopolistic practices.
From this article:
"According to the Post's Hollywood source, Apple's ban of Adobe's Flash technology on the iPhone and iPad is what prompted the government to poke around. "
They really don't have an issue up until now with other frameworks because Adobe didn't have one based with the Flash environment. Now that there is one, Apple is going to restrict anything that talks/looks/smells/acts like an Adobe Flash app on the iPhone. In my opinion, they won't do anything to other frameworks, but they'll enforce the rule just for Adobe. Which brings up the whole monopolistic practices thing.
I believe that many of these translator tools have some kind of common runtime function library which take care of the portions that could not be translated 1:1. Those function could then be pretty constant regardless of your application. That way there would be no real need to decompile the app. but instead just look for usage of those function signatures.
FWIW I find the whole idea of limiting user's choice of tools is a bad move.
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Using PyObjC, you can use Python to write Cocoa applications for OS X. Can I write native iPhone apps using Python and if so, how?
You can use PyObjC on the iPhone as well, due to the excellent work by Jay Freeman (saurik). See iPhone Applications in Python.
Note that this requires a jailbroken iPhone at the moment.
Not currently, currently the only languages available to access the iPhone SDK are C/C++, Objective C and Swift.
There is no technical reason why this could not change in the future but I wouldn't hold your breath for this happening in the short term.
That said, Objective-C and Swift really are not too scary...
2016 edit
Javascript with NativeScript framework is available to use now.
It seems this is now something developers are allowed to do: the iOS Developer Agreement was changed yesterday and appears to have been ammended in a such a way as to make embedding a Python interpretter in your application legal:
SECTION 3.3.2 — INTERPRETERS
Old:
3.3.2 An Application may not itself install or launch other executable
code by any means, including without
limitation through the use of a
plug-in architecture, calling other
frameworks, other APIs or otherwise.
Unless otherwise approved by Apple in
writing, no interpreted code may be
downloaded or used in an Application
except for code that is interpreted
and run by Apple’s Documented APIs and
built-in interpreter(s).
Notwithstanding the foregoing, with
Apple’s prior written consent, an
Application may use embedded
interpreted code in a limited way if
such use is solely for providing minor
features or functionality that are
consistent with the intended and
advertised purpose of the Application.
New:
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. The
only exception to the foregoing is
scripts and code downloaded and run by
Apple’s built-in WebKit framework.
Yes you can. You write your code in tinypy (which is restricted Python), then use tinypy to convert it to C++, and finally compile this with XCode into a native iPhone app. Phil Hassey has published a game called Elephants! using this approach. Here are more details,
http://www.philhassey.com/blog/2009/12/23/elephants-is-free-on-the-app-store/
Yes, nowadays you can develop apps for iOS in Python.
There are two frameworks that you may want to checkout: Kivy and PyMob.
Please consider the answers to this question too, as they are more up-to-date than this one.
An update to the iOS Developer Agreement means that you can use whatever you like, as long as you meet the developer guidelines. Section 3.3.1, which restricted what developers could use for iOS development, has been entirely removed.
Source: http://daringfireball.net/2010/09/app_store_guidelines
Pythonista has an Export to Xcode feature that allows you to export your Python scripts as Xcode projects that build standalone iOS apps.
https://github.com/ColdGrub1384/Pyto is also worth looking into.
The iPhone SDK agreement is also rather vague about whether you're even allowed to run scripting languages (outside of a WebView's Javascript). My reading is that it is OK - as long as none of the scripts you execute are downloaded from the network (so pre-installed and user-edited scripts seem to be OK).
IANAL etc etc.
BeeWare is an open source framework for authoring native iOS & Android apps.
2019 Update:
While Python-iOS development is relatively immature and likely will prevent (afaik) your app from having native UI and functionality that could be achieved in an Apple-supported development language, Apple now seems to allow embedding Python interpreters in Native Swift/Obj-C apps.
This supports importing Python libraries and running Python scripts (even with supplied command-line arguments) directly from your Native Swift/Obj-C code.
My company is actually wrapping our infrastructure (originally written in Python) in a native iOS application! It works very well and communication between the parts can be easily achieved via a client-server model.
Here is a nice library by Beeware with a cookiecutter template if you want to try and run Python scripts in your iOS app: https://github.com/beeware/Python-Apple-support/tree/3.6.
Technically, as long as the interpreted code ISN'T downloaded (excluding JavaScript), the app may be approved. Rhomobiles "Rhodes" framework does just that, bundling mobile Ruby, a lightweight version of Rails, and your app for distribution via the app-store. Because both the interpreter and the interpreted code are packaged into the final application - Apple doesn't find it objectionable.
http://rhomobile.com/products/rhodes/
Even after the latest apple press release - rhodes apps (mobile ruby) are still viable on the app-store. I'd find it hard to believe that tinyPy or pyObjC wouldn't find a place if there is a willing developer community.
You can do this with PyObjC, with a jailbroken phone of course. But if you want to get it into the App Store, they will not allow it because it "interprets code." However, you may be able to use Shed Skin, although I'm not aware of anyone doing this. I can't think of any good reason to do this though, as you lose dynamic typing, and might as well use ObjC.
The only significant "external" language for iPhone development that I'm aware of with semi-significant support in terms of frameworks and compatibility is MonoTouch, a C#/.NET environment for developing on the iPhone.
I think it was not possible earlier but I recently heard about PyMob, which seems interesting because the apps are written in Python and the final outputs are native source codes in various platforms (Obj-C for iOS, Java for Android etc). This is certainly quite unique. This webpage explains it in more detail.
I haven't given it a shot yet, but will take a look soon.