delegation test for doesNotUnderstand / doesNotUnderstandAbout

gistfile1.txt

SuperKlasse {

	// this is the interface in Object
	// if an object does not understand,
	// we look which of the two the class implements,
	// and call the appropriate one.

	doesNotUnderstand { |selector ... args|
		"I am the super class, doesNotUnderstand. I have received the following arguments:\n%\n%\n".format(selector, args).postln;
		"I'll forward to doesNotUnderstandAbout".postln;
		^this.doesNotUnderstandAbout(selector, args)
	}

	doesNotUnderstandAbout { |selector, args, keywordArgumentPairs|
		^"I am the super class, doesNotUnderstandAbout. I have received the following arguments::\nselector:%\nargs:%\nkeywordPairs:%\n"
		.format(selector, args, keywordArgumentPairs)
	}

}

SubKlasse : SuperKlasse {

	// this one implements the new interface.

	doesNotUnderstandAbout { |selector, args, keywordArgumentPairs|
		^"I have correctly received the following arguments:\nselector:%\nargs:%\nkeywordPairs:%\n".format(selector, args, keywordArgumentPairs)
	}



}

SubSubKlasse : SubKlasse {

	// let's suppose, the subclass is older than the interface change, and still forwards to doesNotUnderstand
	// when it receives a call that it doesn't understand, it still calls this one.

	doesNotUnderstand { |selector ... args |
		// do something, and in certain cases, delegate up:
		// this would be wrong, because the superclass implements |selector, args, keywordArgumentPairs|
		^super.doesNotUnderstand(selector, *args)
	}

}


/*

a = SubSubKlasse.new;
a.plink(1, 2, 3);
a.doesNotUnderstand(\plink, 1, 2, 3);


*/