[Rubycocoa-talk] using NSRange, NSRect, and other structs?

[John L. <jo...@jo...>]

I've been doing quite a bit of development with ruby-cocoa, and 
completely enjoying the experience!

However, I'm having difficulty dealing with the Cocoa structures like 
NSRect, NSRange, and so on.  I know there are Ruby classes to manage 
these, and they generally work fine.  But I find that I cannot pass 
those objects directly to the Cocoa methods that use them; instead, I 
must call #to_a.  For example:

	range = self.selectedRange
	# at this point, range is an NSRange object	
	textStorage.removeAttribute(OSX.NSKernAttributeName,
		:range, range.to_a) 	# <-- .to_a needed here!

The same thing seems to be true with NSRect, and probably with any 
struct-based "object" (I realize these aren't first-class objects).

Tonight, I ran into a related problem: NSLayoutManager's 
-lineFragmentRectForGlyphAtIndex:effectiveRange: method needs a 
*pointer* to an NSRange struct.  I tried many possibilities, and 
finally ended up with this:

	# set up a dummy range to have somewhere to store the actual range
	range = [0,0].pack('II')

	rect = layoutManager.lineFragmentRectForGlyphAtIndex(i,
		:effectiveRange, range)

	range = NSRange.new(range.unpack('II'))

This seems neither elegant nor portable, although it does work.

Is there a better way to do this?

PS: I have a sense of deja vu when using Ruby with Cocoa.  Back in the 
mid-1980s, I programmed classic Mac OS (5? 6?) using Think C.  All the 
Apple reference material was in Pascal, so I got to be pretty good at 
*reading* Pascal, but no good at writing it.  I feel much the same 
nowadays: I can't write very good Obj-C programs, but I can read enough 
of it to translate it to Ruby. :)

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