Comments on: Objective-C 3.0 http://losingfight.com/blog/2006/10/25/objective-c-30/ software engineering on the mac Thu, 24 Dec 2009 13:45:24 -0800 http://wordpress.org/?v=2.9.2 hourly 1 By: Psycho http://losingfight.com/blog/2006/10/25/objective-c-30/comment-page-1/#comment-291 Psycho Thu, 06 Nov 2008 10:41:15 +0000 http://www.losingfight.com/blog/2006/10/25/objective-c-30/#comment-291 No need for this feature now, no need to create a new version of Objective-C. Now, you have C-blocks. Apple added support for a new feature : the blocks directly in C (in the llvm-gcc/clang compilers), everything you want is managed here... Except blocks aren't functions so you can add it to a class definition. However, to add methods to a class at runtime, it already exists in the ObjC 2.0 runtime, not through categories but through runtime functions of Objective-C. You can add a method, remove a method, exchange method implementations, etc. No need for this feature now, no need to create a new version of Objective-C.

Now, you have C-blocks. Apple added support for a new feature : the blocks directly in C (in the llvm-gcc/clang compilers), everything you want is managed here… Except blocks aren’t functions so you can add it to a class definition.

However, to add methods to a class at runtime, it already exists in the ObjC 2.0 runtime, not through categories but through runtime functions of Objective-C. You can add a method, remove a method, exchange method implementations, etc.

]]> By: tyler http://losingfight.com/blog/2006/10/25/objective-c-30/comment-page-1/#comment-290 tyler Sat, 20 Oct 2007 04:45:19 +0000 http://www.losingfight.com/blog/2006/10/25/objective-c-30/#comment-290 http://developer.apple.com/documentation/Cocoa/Reference/ObjCRuntimeRef/Reference/reference.html#//apple_ref/c/func/objc_addClass note comment in the sample code: // Allocate empty method lists. // We can add methods later. // http://developer.apple.com/documentation/Cocoa/Reference/ObjCRuntimeRef/Reference/reference.html#//apple_ref/c/func/objc_addClass

note comment in the sample code:

// Allocate empty method lists.
// We can add methods later.
//

]]> By: Mark Aufflick http://losingfight.com/blog/2006/10/25/objective-c-30/comment-page-1/#comment-289 Mark Aufflick Wed, 25 Apr 2007 13:37:30 +0000 http://www.losingfight.com/blog/2006/10/25/objective-c-30/#comment-289 Closures would be hard in Objective-C because it's still, at its core, C. C uses a stack for holding the contexts of the chain of function calls and so has no way to 'hang on to' the context for a closure after the parent function has returned. There is an excellent message on comp.lang.objective-c that explains this better: http://groups.google.com/group/comp.lang.objective-c/msg/37b994ca69cde086 Certainly not impossible, but a whole lot of changing at the core of the language would be required. Closures would be hard in Objective-C because it’s still, at its core, C. C uses a stack for holding the contexts of the chain of function calls and so has no way to ‘hang on to’ the context for a closure after the parent function has returned.

There is an excellent message on comp.lang.objective-c that explains this better:

http://groups.google.com/group/comp.lang.objective-c/msg/37b994ca69cde086

Certainly not impossible, but a whole lot of changing at the core of the language would be required.

]]> By: Andy http://losingfight.com/blog/2006/10/25/objective-c-30/comment-page-1/#comment-288 Andy Thu, 26 Oct 2006 17:45:08 +0000 http://www.losingfight.com/blog/2006/10/25/objective-c-30/#comment-288 Hey Scott, That's great info, I didn't know you could actually add a single method dynamically. It does futher my belief that what I've proposed is feasible. I was worried about my hand-waving when it came to calling anonymous functions. However, it's still not as cool as closures. :-) Hey Scott,

That’s great info, I didn’t know you could actually add a single method dynamically. It does futher my belief that what I’ve proposed is feasible. I was worried about my hand-waving when it came to calling anonymous functions.

However, it’s still not as cool as closures. :-)

]]> By: Andy http://losingfight.com/blog/2006/10/25/objective-c-30/comment-page-1/#comment-287 Andy Thu, 26 Oct 2006 17:41:25 +0000 http://www.losingfight.com/blog/2006/10/25/objective-c-30/#comment-287 Hey Joachim, After writing this article I was convinced that closures are completely doable in Objective-C, albeit with the couple of gotchas that I outlined. I even started wondering if I should download the source to gcc and start tinkering. :-) It would be interesting if someone smarter than I could comment on if I totally missed the boat, and suggested something that's not implementable. Hey Joachim,

After writing this article I was convinced that closures are completely doable in Objective-C, albeit with the couple of gotchas that I outlined. I even started wondering if I should download the source to gcc and start tinkering. :-)

It would be interesting if someone smarter than I could comment on if I totally missed the boat, and suggested something that’s not implementable.

]]> By: Andy http://losingfight.com/blog/2006/10/25/objective-c-30/comment-page-1/#comment-286 Andy Thu, 26 Oct 2006 17:37:12 +0000 http://www.losingfight.com/blog/2006/10/25/objective-c-30/#comment-286 Hey Keith, You're right about fast array enumeration being in Objective-C 2.0. My choice of examples for closures probably wasn't the best one. Fortunately there are lots of better examples of the power of closures out on the web. Hey Keith,

You’re right about fast array enumeration being in Objective-C 2.0. My choice of examples for closures probably wasn’t the best one. Fortunately there are lots of better examples of the power of closures out on the web.

]]> By: Keith Duncan http://losingfight.com/blog/2006/10/25/objective-c-30/comment-page-1/#comment-285 Keith Duncan Thu, 26 Oct 2006 11:57:19 +0000 http://www.losingfight.com/blog/2006/10/25/objective-c-30/#comment-285 Yeah I think I missed the point of what you were saying when I read it this morning, I was mulling it over in my head durning my driving lesson (the instructor was less than pleased with my concentration) and now see what your getting at - a driving lesson evey day for a week can really tire you out! Yeah I think I missed the point of what you were saying when I read it this morning, I was mulling it over in my head durning my driving lesson (the instructor was less than pleased with my concentration) and now see what your getting at – a driving lesson evey day for a week can really tire you out!

]]> By: Joachim Bengtsson http://losingfight.com/blog/2006/10/25/objective-c-30/comment-page-1/#comment-284 Joachim Bengtsson Thu, 26 Oct 2006 09:12:41 +0000 http://www.losingfight.com/blog/2006/10/25/objective-c-30/#comment-284 Closures in a compiled language would be beyond awesome (although I'd guess it's already been done by some language long forgotten...). And with a real syntax, yes please! Not all the mess with "Define a function in the global scope, get a function pointer from that, and inject that into the runtime"... However, perhaps all that's needed is a preprocessor... ;) Next summer project here I come! (It's funny that Objc started as a preprocessor...) Although that wouldn't preserve locals, hmm... Closures in a compiled language would be beyond awesome (although I’d guess it’s already been done by some language long forgotten…). And with a real syntax, yes please! Not all the mess with “Define a function in the global scope, get a function pointer from that, and inject that into the runtime”…

However, perhaps all that’s needed is a preprocessor… ;) Next summer project here I come! (It’s funny that Objc started as a preprocessor…) Although that wouldn’t preserve locals, hmm…

]]> By: Scott Stevenson http://losingfight.com/blog/2006/10/25/objective-c-30/comment-page-1/#comment-283 Scott Stevenson Thu, 26 Oct 2006 08:58:17 +0000 http://www.losingfight.com/blog/2006/10/25/objective-c-30/#comment-283 The future is here now. Categories can load at runtime, and you can also <a href="http://theocacao.com/document.page/327" rel="nofollow">add methods at runtime</a>. You do have to get your hands messy, though. Great post, though. The future is here now. Categories can load at runtime, and you can also add methods at runtime. You do have to get your hands messy, though.

Great post, though.

]]> By: Keith Duncan http://losingfight.com/blog/2006/10/25/objective-c-30/comment-page-1/#comment-282 Keith Duncan Thu, 26 Oct 2006 08:03:43 +0000 http://www.losingfight.com/blog/2006/10/25/objective-c-30/#comment-282 Just a little note on the closures you mention, if you read the web documentation on Obj-C 2.0 it features fast enumeration - faster than an NSEnumberator. So unless im missing something this already covered this in version two by using for(id someObject in array) NSLog(@"%@", [someObject description]); Just a little note on the closures you mention, if you read the web documentation on Obj-C 2.0 it features fast enumeration – faster than an NSEnumberator. So unless im missing something this already covered this in version two by using for(id someObject in array) NSLog(@”%@”, [someObject description]);

]]>