A rough guess at the implementation of +[NSBundle preferredLocalizationsFromArray:]

gistfile1.m

+ (NSArray *)dh_preferredLocalizationsFromArray:(NSArray *)requestedLocalisations
{
	NSMutableSet *possibleLocalisations = [NSMutableSet setWithArray:requestedLocalisations];
	
	BOOL shouldLimitToAvailableLocalisations = YES; // Set to YES to match what NSBundle seems to do, or NO to be more like the documentation.
	
	if (shouldLimitToAvailableLocalisations) {
		[possibleLocalisations intersectSet:[NSSet setWithArray:[[NSBundle mainBundle] localizations]]];
	}
	
	NSMutableArray *preferredLocalisations = [NSMutableArray array];
	
	for (NSString * loc in [NSLocale preferredLanguages]) {
		if ([possibleLocalisations containsObject:loc]) {
			[preferredLocalisations addObject:loc];
			
#warning Need to check it finds a general localisation.
			NSString * const generalLoc = [loc substringToIndex:[loc rangeOfString:@"-"].location];
			if ([possibleLocalisations containsObject:generalLoc]) {
				[preferredLocalisations addObject:generalLoc];
			}
			break;
		}
	}
	
	return preferredLocalisations;
}