[sc-dev] Announcement: Cocoa Bridge

[Ryan Brown <ryan@xxxxxxxxx>]

Hi,
I've been working on a project that I expect many of you will be  
interested in and recently got the core functionality implemented.  
The project is a full Objective-C bridge in the style of PyObjC or  
RubyCocoa. My motivation for writing it is so that users can create  
GUIs in Interface Builder that work seamlessly with SuperCollider.  
I'm hoping to release it towards the end of December.

It supports:
	1- Subclassing Objective-C classes inside of SuperCollider.
	2- Calling Objective-C objects with the same syntax you use to call  
Supercollider objects.
	3- Connecting actions and outlets in Interface Builder to  
SuperCollider objects.
	4- Bindings.

As an example, lets say you wanted to build a simple UI that called a  
method upon pressing a button. First, you would drag a button into a  
window in Interface Builder. Then, still in Interface Builder, you  
instantiate an object named TestClass. You create an action in  
TestClass named test: and connect the button to the action. In  
SuperCollider you create a new class like so:

TestClass : NSObject {
	test_ { arg sender;
		"You hit the test button".postln;
	}
}

Note that the colons in Objective-C are replaced with underscores in  
SuperCollider. You recompile the class library, call a function to  
load the NIB and your UI pops up. Using things like a table view is  
similarly easy; you just implement two more methods:  
tableView_objectValueForTableColumn_row_ and  
numberOfRowsInTableView_. Doing an NSView subclass that draws a  
string and random color looks like:

CustomViewTest : NSView {
	initWithFrame_ { arg frameRect;
		^super.initWithFrame_(frameRect);
	}
	
	drawRect_ { arg rect;
		NSColor.colorWithCalibratedRed_green_blue_alpha_(rrand(0, 1.0),  
rrand(0, 1.0), rrand(0, 1.0), 0.6).set;
		NSBezierPath.fillRect_(rect);
		rect = rect.moveBy(1, -2.2);
		"I'm an NSView subclass running inside of  
SuperCollider".asNSString.drawInRect_withAttributes_(rect, nil);
	}
}

Some things to note: you call Objective-C methods by giving the  
method/argument names first and then the arguments in that order.  
NSRect (a C structure) is transparently bridged with the  
SuperCollider Rect class. As a convenience you can create an NSString  
by calling .asNSString on a SuperCollider string.

Those of you that are familiar with Jan's bridge might be thinking,  
"but hasn't this already been done?". Jan's bridge only supports one  
way communication with Cocoa. You can instantiate Cocoa objects and  
send them messages, but you can't have Cocoa call SuperCollider  
(which essential if you want to use NIB files or create delegates).  
Although I had to rewrite most of his code, my bridge is the next  
step in what he was doing.

Best,
Ryan