NSObject recursive description category, for debugging trees (subviews, sublayers, child view controllers) or chains (superviews, next responders, superclasses).

NSObject+DHRecursiveDescription.m

@interface NSObject (DHRecursiveDescription)

- (NSString *)dh_recursiveDescriptionWithRecursion:(id (^)(id obj))recursion;

@end

@implementation NSObject (DHRecursiveDescription)

- (NSString *)dh_recursiveDescriptionWithRecursion:(id (^)(id obj))recursion
{
	NSMutableString *string = [NSMutableString stringWithString:@"\n"];
	[self dh_recursivelyAddDescriptionToString:string withPrefix:@"" recursion:recursion];
	
	return string;
}

- (void)dh_recursivelyAddDescriptionToString:(NSMutableString *)string withPrefix:(NSString *)prefix recursion:(id (^)(id obj))recursion
{
	[string appendFormat:@"%@%@\n", prefix, [self description]];
	
	id const next = recursion(self);
	
	if ([next respondsToSelector:@selector(countByEnumeratingWithState:objects:count:)]) {
		for (id child in next) {
			[child dh_recursivelyAddDescriptionToString:string withPrefix:[@"\t| " stringByAppendingString:prefix] recursion:recursion];
		}
	}
	else {
		[next dh_recursivelyAddDescriptionToString:string withPrefix:prefix recursion:recursion];
	}
}

@end

// Tree example: logging all subviews of a view
UIView *view;
NSLog(@"%@", [view dh_recursiveDescriptionWithRecursion:^id(id obj) {
    return [view subviews];
}]);

// Chain example: logging all superviews of a view, up to the window
UIView *view;
NSLog(@"%@", [view dh_recursiveDescriptionWithRecursion:^id(id obj) {
    return [view superview];
}]);