gistfile1.m

@implementation LEValueAnimation : CPAnimation
{
	CPView _view;
	CPString _keyPath;
}

- (LEAnimation)initWithView:(CPView)aView keyPath:(NSString)keyPath
{
	self = [super initWithDuration:1.0 animationCurve:CPAnimationLinear];
	if(self)
	{
		if([aView respondsToSelector:@selector(keyPath)]){
			_view = aView;
			_keyPath = keyPath;
		} else {
			return null;
		}
	}
	
	return self;
}

- (void)setCurrentProgress:(float)progress
{
	[super setCurrentProgress:progress];
	var temp = "set"+_keyPath;
	[_view performSelector:temp withObject:progress];
}