Objective -c Tuple

Objective - c does not have native support for Tuples.  However, in most cases an NSArray will suffice.  The difference between a tuple and an array is mostly one of categorization.  Tuples are for bundling things that don't have uniformity while Arrays are expected to have the same type.  With that said, a Tuple can be implemented by using an Array, but with it's array features hidden away.

Below is my implantation for a Tuple by using Blocks and variadic function.

typedef id(^TupleType)(NSInteger);

TupleType Tuple(id obj, ...) NS_REQUIRES_NIL_TERMINATION;

TupleType Tuple(id obj, ...) {

va_list argList;

va_start(argList, obj);

NSMutableArray *mut = [NSMutableArray new];

for (; obj; obj = va_arg(argList, id)){

[mut addObject:obj];

}

va_end(argList);

return ^(NSInteger index){

return index >= mut.count ? nil : mut[index];

};

}

You can use it like this

TupleType t = Tuple([MYObj new], [MYObj new], [MYObj new], nil);

for (int i = 0; i < 3; ++i) 

{

NSLog(@"%@", t(i));

}