[jessejlt]

I am making a project timer so that I can keep track of how much time I spend on... well projects.
I want to do something to the effect:

NSCalendarDate *start;
NSCalendarDate *end;
NSCalendarDate *total;

// Start Timer
start = [ NSCalendarDate calendarDate ];

// Sometime Later
end = [ NSCalendarDate calendarDate ];

total = ( NSCalendarDate * ) ( end - start );

But of course this doesn't work. I'm not sure if it doesn't work because I'm not casting correctly, or if it's not possible to subtract two NSCalendarDate 's... Or both. Is there a better way to do this? If not, is it possible to overload operators in Objective-C?
Somebody please kick me into the right direction.

Also, I have an NSTableView that I would like to row-sort, but I'm having a hard time finding any good examples. Does anyone have any good places to start?

Danka;
jesse ;-)

[Ibson]

Have a look at -[NSCalendarDate years:months:days:hours:minutes:seconds:sinceDate:]

Code:
NSCalendarDate *startDate = [NSCalendarDate calendarDate];
NSCalendarDate *endDate = [NSCalendarDate calendarDate];
int years, months, days, hours, minutes, seconds; 

[endDate years:&years months:&months days:&days hours:&hours 
    minutes:&minutes seconds:&seconds sinceDate:endDate];

Operators cannot be overloaded in Obj-C. Always look at Apple's documentation.

If you just want the number of seconds between two dates, you might just want +[NSDate date] and -[NSDate timeIntervalSinceDate:].

For table view sorting, check out http://cocoadev.com/index.pl?SortingTableViewByColumn (although it's a tad dated now that we have Panther). You can now sort table views using NSSortDescriptor (if Panther-only is okay).