Demonstrates nested sorting using NSSortDescriptors.

Sorting.m

#import <Cocoa/Cocoa.h>

@interface IFEntry : NSObject {}

@property (copy, nonatomic) NSString *company;
@property (strong, nonatomic) NSDate *date;

- (instancetype)initWithCompany:(NSString *)company date:(NSDate *)date;

@end

@implementation IFEntry {}

- (instancetype)initWithCompany:(NSString *)company date:(NSDate *)date
{
	if (self != [super init]) {
		return nil;
	}
	
	_company = [company copy];
	_date = date;
	return self;
}

- (NSString *)description
{
	return [NSString stringWithFormat:@"%@ - %@", _company, _date];
}

@end

int main(int argc, char *argv[])
{
	@autoreleasepool {
		NSArray *entries = @[
			[[IFEntry alloc] initWithCompany:@"Apple" date:[NSDate date]],
			[[IFEntry alloc] initWithCompany:@"Dell" date:[NSDate date]],
			[[IFEntry alloc] initWithCompany:@"Amazon" date:[NSDate date]],
			[[IFEntry alloc] initWithCompany:@"Apple" date:[NSDate dateWithNaturalLanguageString:@"yesterday"]]
		];
		
		NSArray *descriptors = @[
			[NSSortDescriptor sortDescriptorWithKey:@"company" ascending:YES],
			[NSSortDescriptor sortDescriptorWithKey:@"date" ascending:YES]
		];
		
		NSLog(@"%@", [entries sortedArrayUsingDescriptors:descriptors]);
	}

	return 0;
}