[MacRuby-devel] MacRuby and ARC was: Advice for Total Tyro

[Matt Aimonetti]

Python uses a reference counting GC, MacRuby could, in theory,
implement ARC under the cover. It would however make C extensions
really really hard to support.

- Matt

On Sun, Oct 16, 2011 at 11:11 PM, Igor Evsukov <igor.evsukov at gmail.com> wrote:
> Hi Henry,
>
> And it's impossible to make Ruby to use ARC.
>
> Why?
>
> For memory management Objective-C uses a paradigm called "reference
> counting". The idea is very simple – when You need an object – You increase
> it reference count, when You no longer need it – You should decrease it. For
> example
>
> NSString *name = @"Henry";
> //when [[... alloc] init...] called (new object get created) – reference
> count of object is set to 1.
> //who create's object is responsible to delete it
> NSString *greeting = [[NSString alloc] initWithFormat:@"Hello %@",name];
> //assume that greetings in an instance of NSMutableArray
> [greetings addObject:greeting];
> //we no longer need a greeting variable
> [greeting release];
>
> Everything is ok with this model, but You should manually track circular
> references.
> ARC is just a smart preprocessor that knows Cocoa memory conventions and
> add's retain/release/autorelease calls to Your source code. And it can't
> figure out what to with circular references.
> In Ruby we have garbage collector which is acts in whole different way –
> instead of modifying source code it track all created objects and delete
> one's that are no longer accessible from Your program.
> So, basically, ARC and GC are two conceptually different things which are
> even not replaceable by each other(circular references).
> I encourage You to watch a BostonRB talk
> ( http://bostonrb.org/presentations/macruby-what-is-it-and-why-should-i-care-part-1 ) by Joshua
> Ballanco (one of the MacRuby developers). In his talk he sad that GC isn't a
> major issue with bringing MacRuby to iOS.
> On 17 окт. 2011, at 08:43, Henry Maddocks wrote:
>
> On 16/10/2011, at 9:07 PM, Igor Evsukov wrote:
>
> And it's impossible to make Ruby to use ARC.
>
> Why?
>
> Henry
>
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