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Re: GC pros and cons
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Re: GC pros and cons


  • Subject: Re: GC pros and cons
  • From: Philip Aker <email@hidden>
  • Date: Wed, 1 Jul 2009 01:02:24 -0700

On 2009-06-30, at 08:11:20, Bill Bumgarner wrote:
On Jun 30, 2009, at 4:03 AM, Philip Aker wrote:
On 2009-06-25, at 11:11:56, Andy Lee wrote:

Just to be clear, Hamish wrote:


> Compilers conforming to C99 I would trust.
> gcc -fobjc-gc... not so much.


Meaning to me that C99 is a direct descendent of C89 and K&R before that. So that means roughly 30 years of evolvement and nit-picking high and low by a lot of people on nearly all platforms extant. Objective-C 2.0 doesn't seem to have a published standard (like with a language syntax summary as in Appendix A of C99). Apple has a track record of introducing stuff that is subsequently dumped. And gosh, I might not like to be the one who trusted in GC to be around forever and then found out I had to account for all those [[NSThing alloc] initWithImpunity:…] calls in Mac OS X 10.7.

Language features can't be removed, nor can languages be changed rapidly.

Sure and especially for languages that have a standard. I haven't been able to find a published standard for Objective-C 2.0. Say something analogous to n1256 for C99 or the XSD 1.1 recommendation from W3C. What I have is a few informal documents from Apple. The sum of these don't constitute a language standard. They only remark what is currently in vogue at Apple.



The features added to Objective-C have been considered extremely carefully and added with great care.

I don't doubt that at all. But that's not the same as having a formal language description. I'm not sure if the term "peer reviewed" is appropriate, but Objective-C as it stands is an Apple-only technology. That's not the same kind of scrutiny C99 and many other languages come under for their standards submissions.



In the past, changes to the compiler have been integrated back into GCC in a relatively timely fashion. Things have changed; now most of the feature work in Objective-C, including Blocks, is actually developed in the open LLVM repository.

Furthermore, Apple is participating actively in the ANSI C standards committee. Both Garbage Collection and Blocks have been presented to the committee and there is traction for both.

http://www.open-std.org/jtc1/sc22/wg14/www/docs/PostMarkham.htm

And, more specifically:

http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1370.pdf

I didn't notice any mention of a submission to the C standard in the PDF of <http://developer.apple.com/documentation/Cocoa/Conceptual/GarbageCollection/Introduction.html >. So thanks for mentioning it. When that's passed, I'll have less doubts about GC permanence (assuming Objective-C will be a superset of C at that point) but more importantly, have something in C that passes muster on other machine and OS combinations.



Philip Aker echo email@hidden@nl | tr a-z@. p-za-o.@

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