which is the best way to develop a linux-compatible Command Line Utility under Mac OS X Lion? It should parse a really big XML file (up to 300 GB) - probably with libxml - and convert it to somewhat JSON.
With XCode 4 there is the possiblity to develop Command Line Utilities (former Foundation Tools I think). Are these compatible to run on Linux Servers? It would be nice, cause I'm used to Objective-C a little bit.
Another approach would be native C. But I'm really no expert in programming C. Alternatives are maybe Perl or Ruby. PHP as CLI script isn't as fast as needed I think.
Any suggestions which is the easiest and at the same time fastest in context of parsing the XML data way?
Thanks in advance
Marco
With speed being a concern with files of that size, I'd be leaning toward C using libxml2 (available on both platforms) and use the progressive (event driven) interface. Other then that, if you stick to posix I/O, you should be fine.
Mac OS also includes a Python implementation. Python's readily available on Linux and has good libraries for both JSON and XML.
Related
I might be asking something strange here, but I'm unsure where to begin. The thing is that I am considering writing a command line tool on a Mac using Obj-C and the Foundation classes.
But there is a very big risk that I would like to be able to compile it for different Linux distributions to run as a server app in the future.
I understand that it is not a problem in itself to compile Objective-C for Linux, but what I don't understand is the API coverage.
As I have understood it so far I can use GNUStep to compile for linux, but is there a good way for me to get an overview of the API coverage? What I mean is, if I use a class that has been added to the Foundation framework in OSX Lion lets say, how big is the risk of that not being available in GNUStep at that time?
I hope I am asking a question that you guys can understand, basically I want to avoid writing an app that can theoretically be compiled for linux, but not in practice because of missing classes etc.
Thanks!
An opinion: The risk is fairly high. GNU Step is an open source project and dependant on its volunteers to keep it up to date. OS X Lion has a small number of additions to Foundation and AppKit.
Your best option if you want it for *nix in the future will be to write it in generic C/C++ and then thinly wrap it in an NSTask if you want a GUI.
You should be able to check if the API's you're using are available by consulting the GNUStep base API docs.
You may want to target GNUStep as your base if compatibillity is a big concern. Compiling for mac should then be rather trivial, compared to moving the code the other way. Of course you always have the option of helping inplement whatever is missing from GNUStep too.
Hi just wondering how do you start writing programs for MAC OS X?
what language does it use? can I use objective C? which IDE do I use? any licensing fee should I know about.
Thanks.
Mac OS X is a great programming platform, as such you can use just about any language you like.
If you wish to write native applications using the Cocoa framework you'll probably want to be using Objective-C. You can download XCode as an IDE for free.
No licensing fees.
Xcode is the apple supplied IDE, and without external libraries some objective C is always required to build applications.
That being said xcode supports multiple types of langauges, and has extensions for many more - and C++ can be spliced in with objective C code - so if you prefer to code in C++ you can write a quick objective C wrapper and do all your own stuff in C++ - or indeed the langauge of your choice. There are a few other open source IDE's but I don't really recommend them - most of them crash on opening in new versions of Mac OS X.
Xcode is found in the developer package on your second mac install disk, or the latest version (with iphone SDK's) can be downloaded once registering on the Apple Developer Website, which you can become a basic member of for free.
As far as licensing goes, unless you plan to make a game for iOS there are no liscensing fees, unless you want a full subscription to apples developer website, which gives you a few extra things from them.
If your trying to write a game, consider using the SDL library, a cross platform wrapper for whole lot of operating system interface functions, including graphics - or you can use it as I do in combination with OpenGL for full 3D Support, hardware acceleration, ect.
Objective-C + Cocoa
http://developer.apple.com/mac/library/documentation/Cocoa/Conceptual/ObjectiveC/Introduction/introObjectiveC.html
http://developer.apple.com/mac/library/documentation/Cocoa/Conceptual/CocoaFundamentals/Introduction/Introduction.html
Apple suggests XCode
The native libraryfor OS X developed by Apple are called Cocoa. It provides OS X's graphical user interface, and other libraries such as Core Data for database acess, Core Animation for fast easy animation and video features in your software. These libraries are written in a mixture of C and Objective C (which is an extension of the C language). For best performance and best integration with the Mac operating system you should probaby look at developing in C, Objective C and perhaps some C++ as well.
There are some add-on layers that provide acces to the Cocoa libraries from other languages such as Ruby or Python. These are generaly of good quality and work well, so you can use these languages if your aplication does not need the very best performance. They are generaly considered to be easier to learn than the C family of languages and you can become productive very quickly.
Beyond that, you can use languages and toolkits that are platform-independent so your software will can run on Linux or Windows as well as the Mac. For example Python comes with a simple built-in GUI toolkit called Tkinter. You can use more powerful cross-platform toolkits such as Qt or WxWidgets with C or C++ but have excellent bindings for Ruby, Python and other langauges. This is an approach I am using of a project, with Python and Qt.
Others have mentioned Apple's integrated development environemnt (IDE) called XCode. I have only toyed with it, but it looks very powerful for true native development of Cocoa applications.
I just caught one of Google's commercials for Chrome where at the end they mention that it runs on Linux, Mac, and PC. So I started wondering how they are able to develop a program that can run on multiple platforms like that? I have experience with Java, and .Net but only on a windows machine. Java is by design portable, but I wouldn't think Google is using Java for something like Chrome where performance is such a concern.
I understand that each version is going to have some platform specific code, such as for the UI. But there must also be some central code that is reused across each platform. What language is this written in?
Here is an entire article about the development of Chrome. It's mostly written in C++.
Chrome is written in C++, so they will have a significant amount of platform-specific code for each OS. They most likely maintain a separate branch for each OS.
Any reasonably standardized and popular language will do, because the goal is to compile it on all platforms, not create one binary that will work on Windows, MacOSX, Linux, and z/OS. C and C++ are popular choices, because they'll work readily with pretty much anything. Java is a good choice, because it runs on pretty much everything. For applications with low performance requirements, Perl and Python are good.
The important point is to separate out what is platform-dependent from what isn't, since (except in the case of Java or scripting languages) it will probably be necessary to rewrite platform-specific stuff for each platform, and not necessarily in the same language. MacOSX is best programmed in Objective-C, and that's true for no other popular platform.
The programs are supposed to be portable in source level, not binary level. So you only need to compile it for different platforms, not necessary to make one universal binary. In fact, most languages are supported in all modern platforms including UNIX/Windows/Mac, so you can choose from almost all modern lanagues, which C/C++ is prefered by many people. BTW, C++ is the language of Chrome.
Scripting languages like Python/Perl are also good choices. One more thing, Java can be faster than you think - see Eclipse. Even without JNI Technology, Java is still good enough for most applications like JDownloader.
Google had to build different distributions for each OS (ie compiled for each platform as Francis's answer explains) - in fact the Mac OS version only recently became available - the Windows version has been around much longer.
Google Apps are 'thin applications' - the grunt-work is done on their servers.
The Apps are portable in the sense that the front-end is put together using HTML, CSS and Javascript - which are standard (in theory at least) across all browsers.
Google put a lot of effort into building Chrome's Javascript engine to be performant - to ensure any client-side logic is run quickly.
What is the Best way i can do Parsing or Writing into XML using cocoa for mac10.3.9.?
Im mentioning the version of OS specifically because, i read in the documentation like, Mac 10.3.9 sdk does not support NSXML class.?
I Found an OpenSource libaray (libxml), is it the only library i can use????
Please give me some suggestion regarding the above....
Kindly reply Soon...
Thank you
Pradeep.
According to my copy of the documentation, the NSXMLParser class is available on Mac OS X 10.3 and later.
If for some reason you cannot use that, you can also use the Core Foundation XML Parser functions (search for CFXMLParser). This is a C-based API also developed by Apple. It will be deprecated in future versions of Mac OS X (after Snow Leopard), but since you're working on 10.3 that won't be a concern for you.
Many who cannot use those two also use libxml. Objective-C is able to use any C-based libraries with no penalty. I'm fairly certain Mac OS X ships with a copy of libxml you can link to (no need to download, build, or ship the library yourself; though if you want to, you certainly can).
What's best is going to depend on what features you need. Namespaces, for example, aren't fully supported by NSXMLParser in 10.3, but they are supported in 10.4.
Thanks for the replies....
I used libxml for xml parsing, it was working fine.
But still it has some problems like, even if the xml file is half consistent(i mean if the xml is corrupt, it loads the xml file).
libxml with xpath made things quite easy for xml parsing.
I'd like to give Objective-C a try in game programming. The problem is I'd need some tools and libraries for this.
First thing that comes into mind I need is the GUI and graphics library.
What choices do I have?
There are Four non Mac implementations of OpenStep/Cocoa type Objective C platforms:
OpenStep/NextStep : Openstep/NeXT support machines only - Discontinued.
p..... can remember name or find it on web - it's out there somewhere ! - Linux
Cocotron - Windows only
GNUStep Linux/Windows
GNUSTep is the way to go for Linux... I mention there others because 2 and 3 are available in source and they can be used to patch holes in code the GNUStep doesn't have and they might.
When it comes to Graphics library - you may have problems because Apple moved away from the old OpenStep APIs and has kept evolving their APIs far faster than the GNUStep people can play catch up. There is no support for the latest graphics libraries such as Core Animation.
As Objective C is C and C++ friendly you can use any of these libraries as is, or by making the Objective C friendly by making a wrapper.
You may or may not want to be Mac compatible and do versions for that so it may not be important.
If you do you might want to do a Linux Wrapper for something like OpenGL if it is missing, which I think it is but have a check yourself....
There are Linux development tools including a project IDE and GUI builder for GNUStep on Linux.
Tony
I believe you're asking for GNUStep.
SDL is a C library which is popular for game programming.
If you're looking for Foundation/AppKit stuff you can also look at Cocotron. I've never tried it though.
Supporting SDL there are Objective-C bindings here. However since Objective-C is a thin OO layer on top of C you can use most of the existing C libs for game development, SDL, Clanlib, etc...