I have a little script I wrote in python and it actually works on the iPhone via the terminal. I am looking for code snippets or documentation for the GUI writing for the iPhone -
Actually what I need is to implement an input and some output.
nothing fancy - for now.
I have found this page: http://www.saurik.com/id/5
but as i understand from the article i will need to write it in objective-c which i am not familiar with - do i have to? or can i write in python or just C?
and it is very descriptive, looking for more docs...
Thanks Alot :)
You cannot write an iPhone app in Python that will run on non-jailbroken phones. Apple's SDK license prohibits interpreted code on the iPhone, which definitely excludes Python. Although you can write OS X apps in Python using PyObjC, you still need to understand the Objective-C language both for documentation and for groking the many Cocoa patterns that are closely tied to Objective-C's way of doing things.
Learn Objective-C. For a programer that knows C or C++, it takes only a couple of days to become proficient in Objective-C. If you've never used a language that has pointers before, it may take a little longer. On the flip side, embracing Objective-C's dynamic nature is much easier for developers coming from dynamic languages as opposed to statically typed languages like C/C++/Java/C#.
There is a GUI sample in that link. The whole app is written in Python with ObjC runtime (but no ObjC code involved).
Still, the ObjC "feel" cannot be avoided because UIKit is designed for and uses ObjC. Note that the GUI programmed in Python is extremely slow on the iPhoneOS. Python can be used as testing, but never release an (interpreted) iPhoneOS Python GUI app to public.
Related
Simple question really, however there doesn't seem to be a straight answer in the current developer documentation.
Does Swift compile to machine language (i.e. assembly), or does it compile to some intermediary form that then runs on a virtual machine?
(I suspect it does, but being unfamiliar with development in Apple's world it is not clear to me like it may be to someone who is.)
Yes, it compiles to machine language by way of LLVM Bitcode and, as #connor said, runs on top of the Objective-C runtime.
Swift not only compiles to native machine code but it has also been designed specifically for it. Unlike e.g. Java which has been designed specifically as a JITed language. By that I mean Swift achieves best performance with ahead of time compilation while Java benefits most from JITing.
There are many reasons for these design choices but among them is that Swift has a much bigger scope than managed languages like Java. It is supposed to work on both desktop computers and phones with more restricted hardware. You can use Swift as a systems programming language unlike say C#, Java or Python because it has little runtime requirements and allow fairly detailed control of memory. So in theory one should be able to build an OS kernel with Swift which would be difficult with say Java.
Swift, just like objective-c compiles to native code using llvm
A good explanation can be found in Apple's top secret Swift language grew from work to sustain Objective C, which it now aims to replace
From that article, talking about Swift
The compiler is optimized for performance, and the language is
optimized for development, without compromising on either.
Swift, like Objective-C, is compiled to machine code that runs on the Objective-C runtime.
I have integrated Lua with my ObjC code (iphone game). The setup was pretty easy, but now, I have a little problem with the bridging. I have googled for results, etc... and it seems there isn't anything that could work without modifications. I mean, I have checked luaobjc bridge (it seems pretty old and dicontinued), I heard about LuaCocoa but it seems not to work on iphone, and wax is too thick.
My needs are pretty spare, I just need to be able to call objc methods from lua and don't mind having to do extra work to make it work (I don't need a totally authomatic bridging system).
So, I have decided to build a little bridge myself based on this page http://anti-alias.me/?p=36. It has key information about how to accomplish what I need, but the tutorial is not completed and I have some doubts about how to deal with method overloading when called from lua, etc...
Do anybody know if there exist any working bridge between objc and lua on the iphone or if it could be so hard to complete the bridge the above site offers?
Any information will be welcomed.
Don't reinvent the wheel!
First, you are correct that luaobjc and some other variants are outdated. A good overview can be found on the LuaCocoa page. LuaCocoa is fine but apparently doesn't support iPhone development, so the only other choice is Wax. Both LuaCocoa and Wax are runtime bridges, which means that you can (in theory) access every Objective-C class and method in Lua at the expense of runtime performance.
For games and from my experience the runtime performance overhead is so significant that it doesn't warrant the use of any runtime binding library. From a perspective of why one would use a scripting language, both libraries defy the purpose of favoring a scripting language over a lower-level language: they don't provide a DSL solution - which means you're still going to write what is essentially Objective-C code but with a slightly different syntax, no runtime debugging support, and no code editing support in Xcode. In other words: runtime Lua binding is a questionable solution at best, and has lots of cons going against it. Runtime Lua bindings are particularly unsuited for fast-paced action games aiming at a constantly high framerate.
What you want is a static binding. Static bindings at a minimum require you to declare what kind of methods will be available in Lua code. Some binding libraries scan your header files, others require you to provide a special declaration file similar to a header file. Most binding libraries can use both approaches. The benefit is optimal runtime performance, and being able to actually design what classes, methods and variables Lua scripts have access to.
There are but 3 candidates to bind Lua code to an iPhone app. To be fair, there are a lot more but most have one or more crucial flaws or are simply not stable or for special purposes only, or simply don't work for iPhone apps. The candidates are:
tolua and tolua++
luabind
SWIG
Big disadvantage shared by all Lua static binding libraries: none of them can bind directly to Objective-C code. All require to have an additional C or C++ layer available that ultimately interfaces with your Objective-C code. This has to do with how Objective-C works as a language and how small a role it has played (so far) when it comes to embedding Lua in Objective-C apps.
I recently evaluated all three binding libraries and came to enjoy SWIG. It is very well documented but has a bit of a learning curve. But I believe that learning curve is warranted because SWIG can be used to combine nearly any programming and scripting language, it can be advantageous to know how to use SWIG for future projects. Plus, once you understand their definition file implementation it turns out to be very easy (especially when compared to luabind) and considerably more flexible than tolua.
OK, bit late to the party but in case others come late also to this post here's another approach to add to the choices available: hand-code your LUA APIs.
I did a lecture on this topic where I live coded some basic LUA bindings in an hour. Its not hard. From the lecture I made a set of video tutorials that shows how to get started.
The approach of using a bindings generation tool like SWIG is a good one if you already have exactly the APIs that you need to call written in Objective-C and it makes sense to bring all those same API's over into LUA.
The pros of the hand-coding approach:
your project just compiles with one standard Xcode target
your project is all C & Obj-C
the LUA is just data shipped along with your images
no fiddling with "do I check in generated code" to Git
you create LUA functions for just the things you want
you can easily have hosted scripts that live inside an object
the API is under your control and is well known
dont expose engine APIs to level building team/tools
The last point is just that if you have detail functions that only make sense at the engine level and you don't want to see those when coding the game play you'll need to tell SWIG not to bind those.
Steffens answer is perfect and this approach is just another option, that may suit some folks better depending on the project.
For an App that is not going to be released on the AppStore I'm looking to embed an interpreter for easy scripting needs. Since I don't really like to get down with pure C, the interpreter should be an Objective C library.
While searching the web I've come across a couple of script interpreters for Objective C but whether those guys work on iPhone is not quite so clear. The one I found that apparently works well on iPhone is LuaCore which brings Lua scripting to iOS Apps.
Which Objective C scripting interpreters have you successfully embedded in iOS Apps?
Some Javascript options:
Using a headless WebKit instance
Instantiate a custom build of JavaScriptCore
CouchBase's attempt at getting SpiderMonkey running (more modern Javascript than V8)
Notice that the JS option will provide with a quite raw runtime environment, you'll probably need to write at least some of it yourself for it to be a convenient development environment.
Other languages:
An attempt with Python.
Clojure by way of a static build of JavaScriptCore (see point 2 above).
The Nu language is also supposed to integrate well, and have a good Objective-C bridge.
I have only tried the first headless WebKit variant for Javascript, but plan to try as many of those listed as possible for a project during the coming months.
Update:
I've used the Javascript method 1 (headless WebKit) a bit longer. I got it running quite effortlessly, and will stick with that for a while. But it has a huge drawback: you can't call back to native in an easy manner. I solved this by writing a PhoneGap inspired bridge that empties a command queue after the script has run.
I've also tried Python using the link I gave. I made it compile and execute some sample code, but it suffers from the same problem as using Js via headless WebKit, and since it consumes quite a bit of memory I skipped it for now. A callback command queue in the same spirit as the one I created with Js would be possible though. Another Python method would be to attempt to call into the Objective C runtime using ctypes. That approach is described in this answer.
Update 2: Here are several new(ish) links for running Scheme, with both interpreter and compilation options.
I just stumbled upon a really decent description by Twitter user #mysterycoconut of how to get Lua support up and running.
Just discovered a post regarding scripting on iOS at answerspice.com.
Based on the post I evaluated Nu and had it up and running pretty quickly based on the Xcode project referenced in this discussion (thanks Tim!). I tested in the simulator and on an iPhone 4. So Nu is definitely among the scripting languages that can be embedded in an iOS App.
Is there anyway to load an objective c script at runtime, and run it against the classes/methods/objects/functions in the current iPhone app?
MAJOR NOTE: The major reason I'd like to do this is to allow me to rapidly prototype an application, and then, after I'm done a major prototyping phase, take the scripts I was writing and compile them at build time instead. I don't ever plan on shipping an app with an objective c interpreter in it.
The reason i ask is that I've been playing around with iPhone wax, a lua interpreter that can be embedded in an iPhone app, and it works very nicely, in the sense that any object/method/function that's publically available in your Objective C code is automatically bridged, and available in lua.
This allows you to rapidly prototype applications by simply making the core of your app be lua files that are in the users documents directory. Just reload the app, and you can test out changes to your lua files without needing to rebuild the app in XCode - a big time saver!
But, with Apples recent 3.1.3 SDK stuff, it got me thinking that the safest approach for doing this type of rapid prototypeing would be if you could use Objective C as the interpreted code... That way, worst case scenario, you could just compile it into your app before your release instead. I have heard that the lua source can be compiled to byte code, and linked in at build time, but I think the ultimate safe thing would be if the scripted source was in objective c, not lua. That way your source is always in objective c, regardless.
This leads me to wondering (i've searched, but come up with nothing) if there are any examples on how to embed an Objective C Interpreter in an iPhone app? This would allow you to rapidly prototype your app against the current classes that are built into your binary, and, when your about to deploy your app, instead of running the classes through the in app interpreter, you compile them in instead.
With the iPad and OS 4, bluetooth and virtual keyboards can work with iPhones and iPads... That's going to make this type of rapid prototyping something much more useful, at least for dev time. If you have an interpreter built into your app and have it on your iPad, for example, you can code against the interpreter while on the road, without XCode. And to me, the most useful way to get the source back to an "apple approved" state would be if the scripts were Objective C.
Objective-C is really just C with a runtime and some syntactic sugar. It's an inherently compiled language (I don't think there are any production-ready interpreters for C, although I might be wrong).
Xcode used to have a feature called ZeroLink to speed up compile time, but removed it in Xcode 3 because it caused too many bugs.
It's not exactly impossible, but it wouldn't be easy enough to be worth it. Objective-C isn't normally an interpreted language. This isn't insurmountable — interpreted vs. compiled is just an implementation choice in most cases. For example, Ruby is traditionally considered an interpreted scripting language, but MacRuby compiles it down to code just like Objective-C produces. So it would be possible to write an interpreter for Objective-C, but nobody has done this. You would have to write it yourself.
Also, the rules forbid interpreters other than Apple's Javascript interpreter. So far this hasn't been enforced on anyone, but if you're trying to be a very straight arrow, interpreted code is unfortunately out as well.
Well, there's a couple worthwhile points to bring up:
Why interpret Objective-C code when you can compile it? I understand the "rapid prototyping" idea, but part of the reason to do that in, e.g., Lua, is because Lua is a much terser language than Objective-C. I don't know if interpreting Objective-C will have as much of a bonus.
If you want to have plugins or dynamically-loadable modules in your app, you can always compile them as a separate bundle and load them, using NSBundle or a similar mechanism.
All that said, I don't know of any Objective-C interpreters. You'd likely have to write your own. I'm not sure if it would violate Apple's guidelines or not: it'd still be Objective-C code, but I thought they had rules against interpreted code, too. (I suppose they never envisioned a hypothetical scenario in which Objective-C was interpreted, though.)
There is a basic Objective-C interpreter:
Check out the posting:
Is there an Objective-C Interpreter for the Mac?
Also:
http://forrst.com/posts/Beginnings_of_a_Objective_C_Interpreter-Tdl
Ch is a commercial C/C++ interpreter. It's made by a company called SoftIntegration.
Not on IPhone, but on Simulator, you can do this with
Dynamic Code Injection Tool
http://dyci.github.com/
There's also another tool, that works a little different way, but allows same functionality
http://injectionforxcode.com/
You should take a look at cycript. You can hook into apps, replace methods on the fly, change variables, you-name-it. It's an hybrid language between Objective-C and JavaScript.
You'll need to jailbreak your iDevice to install it.
Take a look at the documentation for objc_msgSend() and other parts of the Objective-C Runtime Reference. You can essentially parse text and send it to the runtime.
Now that monotouch is banned, I was wondering if there is a way to translate C# (or some other language) into Objective-C? I won't mind using Apple's API as long as I don't have to declare my variables in 3-4 stages (ivar-property-synthesize-dealloc). All I want is a less wordy language, to concentrate on my intent and not on the compiler syntax.
You should pause to see what actually happens instead of assuming Monotouch is banned.
Or, learn Objective-C. It's good for the mind to learn a new language anyway. And the frameworks will make more sense to you.
You could always define your own meta language for objects, write your intended meaning, parse that file, and paste the newly manufactured code into XCode.
And if you're really dead-set against ObjC and XCode, Apple has given you your ultimatum: use it or leave.
If it turns out the way people are suggesting it will turn out, then the answer to your question doesn't actually solve your problem.
The SDK agreement make specific mention to the 'originality' of the Objective-C (and other languages). Translating from C# to Objective-C breaches this requirement that applications be originally written in Objective-C.
Secondly, Monotouch already supports full AOT compilation.
Translating would be against Apples policy because your code must be originally coded in C, Obj -C, C++.
Coming from originally learning Java its really not that hard. Is the declaration of variables in multiple places really your main objection? Its easy to do and gives you tight control over your program. It is also suspected that iPhone OS 4 needs native code to be able to multitask properly. It makes sense as well otherwise they would of amended the current licence agreement if they wanted to stop Adobe.
This is something I wrote last year and may help you with the transition - Objective C by example for a C# developer, assuming Monotouch is actually forbidden.