[MacRuby-devel] Behaviour when local variables pointing to non-auto-retained objects go out of scope?

[Michael Johnston]

Note that I'm aware {{{ image =  
NSImage.alloc.initWithContentsOfFile("stretch.tiff") }}} should be  
{{{ image = NSImage.new.initWithContentsOfFile("stretch.tiff") }}}, I  
just forgot to change back one of my experiments. It doesn't affect  
anything in this example though.

Cheerio,

Michael Johnston
lastobelus at mac.com




On 5-Jan-10, at 1:30 AM, Michael Johnston wrote:

> I just purchased the book Programming Cocoa with Ruby, and am  
> working through the examples using Macruby.
>
> This tiny app works fine in rubycocoa, but in macruby the created  
> statusbar item immediately disappears.
>
> {{{
> #!/usr/bin/env macruby
> framework 'cocoa'
>
> class App
>  def applicationDidFinishLaunching(aNotification)
>    statusbar = NSStatusBar.systemStatusBar
>    status_item =  
> statusbar.statusItemWithLength(NSVariableStatusItemLength)
>
>    image = NSImage.alloc.initWithContentsOfFile("stretch.tiff")
>    raise "Icon file 'stretch.tiff' is missing." unless image
>
>    status_item.setImage(image)
>  end
> end
>
> NSApplication.sharedApplication
> NSApp.delegate = App.new
> NSApp.run
>
> }}}
>
> I assumed this had to do with garbage collection because in obj C  
> status_item would have to be retained, and so I changed  
> "status_item" to "@status_item"  and then it works fine.
>
> However while playing around with it I also noticed that if I leave  
> status_item as a local var and add a "sleep 1" at the end of  
> applicationDidFinishLaunching, it also works fine and the status  
> item never disappears.
>
> So now I'm not sure whether there is a bug or not. In general, what  
> is the intended behaviour of Macruby with local variables referring  
> to objects that would have to be retained in obj C when said  
> variables go out of scope?
> Cheerio,
>
> Michael Johnston
> lastobelus at mac.com
>
>
>
>
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