NSUserDefaults for Command-Line Arguments

NSUserDefaults along with it’s standard usage scenario can also be used to parse command line parameters. It’s just matter of getting shared instance and calling -stringForKey: and other methods:

#import <Foundation/Foundation.h>

int main (int argc, const char * argv[]) {
   NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

   // Get shared instance
   NSUserDefaults *args = [NSUserDefaults standardUserDefaults];

   // Get parameters
   NSString *task = [args stringForKey:@"create"];
   NSInteger num  = [args integerForKey:@"num"];
   
   // Do something with them
   if(task && num > 0) {
      NSLog(@"Create \"%@\" #%i", task, num);      
   } else {
      NSLog(@"usage: args -create <task name> -num <number>");
   }
   
   [pool drain];
   return 0;
}

The parameters are parsed using "-key value" semantics:

~/Cocoa/args/build/Debug$ ./args -create picture_of_the_day -num 101
2009-02-03 19:12:54.741 args[4109:10b] Create "picture_of_the_day" #101

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