Oleg Andreev



Software designer with focus on user experience and security.

You may start with my selection of articles on Bitcoin.

Переводы некоторых статей на русский.


Product architect at Chain.

Author of Gitbox version control app.

Author of CoreBitcoin, a Bitcoin toolkit for Objective-C.

Author of BTCRuby, a Bitcoin toolkit for Ruby.

Former lead dev of FunGolf GPS, the best golfer's personal assistant.


I am happy to give you an interview or provide you with a consultation.
I am very interested in innovative ways to secure property and personal interactions: all the way from cryptography to user interfaces. I am not interested in trading, mining or building exchanges.

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August 6

Fixing modern Objective-C syntax with subscripting for iOS 5 and iOS 4

Xcode 4.4 is capable of subscript syntax and allows migrating the code from [arr objectAtIndex:0] to arr[0]. A few tweaks needed, however:

1. While OS X 10.8 SDK already contains objectAtIndexedSubscript: and objectForKeyedSubscript:, iOS 5.1 SDK does not. To make compiler happy, you should add this:


#if __IPHONE_OS_VERSION_MAX_ALLOWED < 60000
@interface NSDictionary(IGSubscripts)
- (id)objectForKeyedSubscript:(id)key;
@end

@interface NSMutableDictionary(IGSubscripts)
- (void)setObject:(id)obj forKeyedSubscript:(id )key;
@end

@interface NSArray(IGSubscripts)
- (id)objectAtIndexedSubscript:(NSUInteger)idx;
@end

@interface NSMutableArray(IGSubscripts)
- (void)setObject:(id)obj atIndexedSubscript:(NSUInteger)idx;
@end
#endif

2. To deploy new stuff back to iOS 5 and iOS 4, you need ARCLite. Somehow ARC itself works without extra configuration, but subscripting requires explicit linker flag:

In project settings add to Other Linker Flags: “-fobjc-arc”

3. If you use Edit -> Refactor -> Convert to Modern Objective-C Syntax, it will replace -[NSLocale objectForKey:] with a square brackets syntax, which is not supported by NSLocale. This is the only bug I have found with the automatic translation. NSCache and NSUserDefaults are not touched by the migrator.