Today in Ugly Code

main.m

//
//  main.m
//  Zip
//
//  Created by Julius Parishy on 8/2/13.
//  Copyright (c) 2013 Fitocracy. All rights reserved.
//

#import <Foundation/Foundation.h>

#include <stdarg.h>

NSArray *zip(id(^map)(NSArray *objs), int count, NSArray *first, ...)
{
    va_list ap;
    va_start(ap, first);
    
    NSMutableArray *allArrays = [NSMutableArray array];
    [allArrays addObject:first];
    for(int i = 0; i < count - 1; ++i)
    {
        [allArrays addObject:va_arg(ap, NSArray *)];
    }
    
    NSArray *arrays = [allArrays sortedArrayUsingComparator:^NSComparisonResult(NSArray *array1, NSArray *array2) {
        
        return [@(array1.count) compare:@(array2.count)];
    }];
    
    NSMutableArray *zipped = [NSMutableArray array];
    
    NSInteger iterationCount =  [arrays[0] count];
    for(NSUInteger i = 0; i < iterationCount; ++i)
    {
        NSMutableArray *objs = [NSMutableArray array];
        for(NSArray *array in arrays)
        {
            [objs addObject:array[i]];
        }
        
        [zipped addObject:map([objs copy])];
    };
    
    va_end(ap);
    
    return [zipped copy];
}

@interface Person : NSObject

@property (nonatomic, copy) NSString *firstName;
@property (nonatomic, copy) NSString *lastName;

@property (nonatomic, assign) int age;

@end

@implementation Person
-(NSString *)description
{
    return [NSString stringWithFormat:@"%@ %@, %d", self.firstName, self.lastName, self.age];
}
@end

int main(int argc, const char * argv[])
{

    @autoreleasepool {
        
        NSArray *firsts = @[ @"Julius", @"Bob", @"Ted" ];
        NSArray *lasts  = @[ @"Parishy", @"Smith", @"Mosby" ];
        NSArray *ages   = @[ @20, @42, @30 ];
        
        NSArray *zipped = zip(^Person *(NSArray *objs) {
        
            Person *person  = [[Person alloc] init];
            person.firstName = objs[0];
            person.lastName  = objs[1];
            person.age       = [objs[2] integerValue];
            
            return person;
        }, 3, firsts, lasts, ages);
        
        NSLog(@"%@", zipped);
    }
    
    return 0;
}

Output

2013-08-02 11:37:42.612 Zip[36780:303] (
    "Julius Parishy, 20",
    "Bob Smith, 42",
    "Ted Mosby, 30"
)