objc block closure

closure.m

- (void)setHighlighted:(BOOL)highlighted animated:(BOOL)animated duration:(NSTimeInterval)duration completion:(void(^)(BOOL finished))completion {

    void (^highlight)(UIView *, BOOL) = ^void(UIView *view, BOOL highlight) {
        if (highlight) {
            view.layer.borderWidth = 0.0;
            view.layer.borderColor = [UIColor clearColor].CGColor;
            view.layer.shadowOpacity = 0.0;
        }
        else {
            view.layer.borderWidth = 1.0;
            view.layer.borderColor = [UIColor blackColor].CGColor;
            view.layer.shadowOpacity = 2.0;
            view.layer.shadowColor = [UIColor yellowColor].CGColor;
            view.layer.shadowOffset =  CGSizeMake(0, 0);
            view.layer.shadowRadius = 5.0;
        }
    };
    
    if (animated) {
        [UIView animateWithDuration:duration animations:^{
            highlight(self, highlighted);
        } completion:completion];
    }
}