mattjgalloway

/**
 * I have a URL and a UUID stored in UserDefaults, both as String.
 * I want to extract both and convert the UUID string into an actual UUID.
 * Here is something strange...
 */
 
// This works on iOS. But on watchOS, the guard returns, even though the URL and UUID exist in UserDefaults
guard
  let accountURL = UserDefaults.standard.string(forKey: UserDefaultKeys.accountURL.rawValue),
  let accountUUIDString = UserDefaults.standard.string(forKey: UserDefaultKeys.accountUUID.rawValue),

mattjgalloway

// On iOS...

// This doesn't crash:
id null = @[[NSNull null]];
dispatch_block_t block = (dispatch_block_t)null[0];
block();

// This does:
id null = [NSNull null];
dispatch_block_t block = (dispatch_block_t)null;

mattjgalloway

(lldb) p (int) [0x7d35ec40 hash]
(int) $14 = 16406

(lldb) p (int) [0x79bef090 hash]
(int) $15 = 22

(lldb) p (BOOL) [0x79bef090 isEqual:0x7d35ec40]
(BOOL) $16 = YES

(lldb) p (BOOL) [0x7d35ec40 isEqual:0x79bef090]

mattjgalloway

#import <Foundation/Foundation.h>

typedef NS_ENUM(NSUInteger, MyEnum) {
  MyEnumA = 1 << 0,
	MyEnumB = 1 << 1,
	MyEnumC = 1 << 2,
	MyEnumD = 1 << 3,
	MyEnumE = 1 << 4,
	MyEnumF = 1 << 5,
	MyEnumG = 1 << 6,

mattjgalloway

#import <UIKit/UIKit.h>
#import <objc/runtime.h>

@interface NSObject (MJGResponds)
+ (BOOL)mjg_hasImplementationForSelector:(SEL)selector searchUntilClass:(Class)cls;
@end

@implementation NSObject (MJGResponds)

+ (BOOL)mjg_hasImplementationForSelector:(SEL)selector searchUntilClass:(Class)cls {

mattjgalloway

@interface SubclassNSObject : NSObject
@property (nonatomic, strong) SubclassNSObject *other;
@end

@implementation SubclassNSObject
@end

@interface SubclassUIViewController : UIViewController
@property (nonatomic, strong) SubclassUIViewController *other;
@end