Sparrow Forum

1. 

   enbr
   Moderator

   I saw a post about using Lua and Sparrow a while back and decided to try it.
   I was able to get a Scaffold like project running and thought I would share it!
   There are a number of important things to know, like the difference between . and : and the lack of macros, but I will probably make a tutorial later. For now, post any questions here.

   http://cl.ly/262t2U1e3v3h0I0I0l2E

   Also, here are some benefits of Lua from this article:
   http://mobile.tutsplus.com/tutorials/iphone/iphone-wax/
   Why use Wax?
   Wax is free and open-source. Unlike some other Lua based solutions for mobile development, Wax is an open-source framework that only requires you invest a little bit of time to get working, not money. Don’t like the way Wax works or find a bug in the implementation? The source-code is freely available, and you can always modify it to fit your needs.
   You can leverage native APIs. This means tutorials written to teach Objective-C can be easily adapted and written with Lua for Wax. This also means your app will always look and feel native, yet you still have the time-saving benefit of writing your code in Lua, an efficient scripting language.
   You get to use Xcode. This means that both simulator and device deployment is a snap and shouldn’t break easily with a future iOS release.
   You get to leverage all existing Objective-C libraries. If you have an Objective-C class that you have written before, you can use it in Lua–with no adaptations–you just toss it into Xcode. Same thing goes for libraries like Three20. Just add them per the normal instructions and you have access to them in your Lua code.
   You get to leverage Wax Lua modules. Wax has a few built in Lua modules that make asynchronous HTTP requests and JSON creation/parsing incredibly easy and fast (because the modules are written in C).
   You don’t have to manage memory. No more memory allocation and the like. Wax handles all of that for you.
   Lua types are automatically converted to Objective-C equivalents and vice-versa. This means that when you call a method that needs an NSString and an NSInteger, but you pass a Lua string and a Lua integer, Wax will take care of it for you. This conversion is even powerful enough to handle complex Objective-C features like selectors.
   You get to leverage ALL of the above. No need to pick and choose. You get it all!

   Posted 11 months ago #
2. 

   Daniel
   Primary Feather

   Wow, that's awesome, Brian! I've looked at Wax, too, but I never found the time to really try it out.

   I downloaded your sample, and the code looks really simple to write -- as you said, you just have to know how the methods and classes are to be used from within Lua, and everything is available.

   To become really intuitive to use, I'm thinking about adding an additional Lua-Layer above the Wax wrapper, so that it feels and codes just like it was a Lua API from the beginning. It will take a while before I have the time to do that, but it's on my TODO-List/Road Map

   Thanks for trying it out and sharing your results! If you find the time to write the tutorial, it would be really great -- I'm sure a lot of users would be interested in that. I'd promote the tutorial on the blog, promised

   BTW, congratulations for submitting "Squares" to Apple! I'm crossing my fingers for you that everything runs smoothly -- I know you worked hard on that game!! I will try it out as soon as it's in the store

   Posted 11 months ago #
3. 

   enbr
   Moderator

   Thanks for the Squares encouragement!
   Wait, how did you know I submitted it?

   About Wax: I've never really used the Lua API but the features are awesome, especially the automatic memory management! I'm pretty content with the Wax API for now. One thing that takes some getting used to is the lack of a .h equivalent. Also, there are no macros, do you know how to get around that?

   Brian

   Posted 11 months ago #
4. 

   Navi
   Member

   Interesting stuff - But I don't quite get what Wax will buy me? Is there any advantage other than garbage collection? Aren't the modules for JSON, AHTTP, ... also available as open source objective c libraries?

   I am not trying to be down on this. Just trying to understand how I can use Wax / Lua.

   Posted 11 months ago #
5. 

   enbr
   Moderator

   I'm not sure really what ALL the advantages are, but I think the automatic memory management is pretty impressive. I have spent hours on Squares working out memory bugs! Also, Lua seems very efficient. Another game engine (whose name we shall not say) uses Lua and people put together impressive games in a matter of days and weeks with it!
   Other than that I'm not sure, and I'm not trying to say Lua is the ultimate language, it is just an alternative.

   Posted 11 months ago #
6. 

   saumya
   Member

   hey Brian,
   thats some cool news. I will give a try as I was struggling to get the WAX logic. I tried learning WAX, and the main thing which keeps me back is the documentation. WAX is quite straight forward in that way, but as you are discussing above, it needs some getting used to understanding. I hope your code example would be a good start.
   I hope Daniel will finish his todo list very fast an API wrapper on top would be seamless to jump start LUA.
   Complete advantages I think I am not sure, but working in a dynamic language like LUA will just make it easier for script(javascript,actionscript) writers to jump start iPhone applications. That would be huge advantage to tap in the community, who are creative but need a tool to easily demonstrate what could be done.

   Posted 11 months ago #
7. 

   saumya
   Member

   hi,
   while trying to run the default project of Brian, I came into following error,

   Command /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/llvm-gcc-4.2 failed with exit code 1

   Are there any settings I am missing! Please help me fix this prolem.

   Posted 11 months ago #
8. 

   saumya
   Member

   well digging a little further it says the following error,

   ld: library not found for -lSparrow
   collect2: ld returned 1 exit status
   Command /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/llvm-gcc-4.2 failed with exit code 1

   Any help will be a huge help.
   thanks.

   Posted 11 months ago #
9. 

   Jugibur
   Moderator

   @saumya,
   just delete "libSparrow.a" from the "Frameworks"-folder and it will build.

   And thanks to you, Brian, for this base project!

   Juergen

   Posted 11 months ago #
10. 

    saumya
    Member

    hey Jugibur, thanks a lot. Thats worked like a charm.
    After deleting 'libSparrow.a' can I use sparrow too!! And how is this .a files are related in objectiveC.
    thanks a lot.

    Posted 11 months ago #
11. 

    freerunnering
    Moderator

    .a files are precompiled source code.

    Your source code normally is compiled into a binary but if you want to add library's to your app (that don't need to be recompiled as they won't be changed) then the source code can be compiled into a .a file. This is the code precompiled, but not linked with the other code into a binary file.
    It's only really to speed up the time it takes to compile.

    To use sparrow without the .a file just drag the files directly into your project from, sparrow/src/classes/.

    Posted 11 months ago #
12. 

    saumya
    Member

    thank you freerunnering, thats a huge help.
    the problem is I want to use .a files of Sparrow, but as I said it does not compile correctly, throwing errors. Is there a way to fix that without deleting the .a file.
    Well one more thing is, while removing the .a file does compile it without error, if I try to run it in the simulator without going through xcode, it crashes!

    Posted 11 months ago #

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