How to Extract AppleScript Data from a NSAppleEventDescriptor in Cocoa and Parse it

Question

What I'm doing is executing an AppleScript inside of Cocoa. It returns some data as a NSAppleEventDescriptor, which NSLog() prints like so:

<NSAppleEventDescriptor: 'obj '{ 'form':'name', 'want':'dskp', 'seld':'utxt'("69671872"), 'from':'null'() }>

I want to take that data and turn it into a NSDictionary or NSArray, or something useful so I can extract stuff from it (specifically I'm after the field holding the "69671872" number). It appears to be an array of some sort, but my knowledge with Apple Events is fairly limited. Any idea on how to do this?

Here's the source creating the above data:

NSString *appleScriptSource = [NSString stringWithFormat:@"tell application\"System Events\"\n return desktop 1\n end tell"];
NSDictionary *anError;
NSAppleScript *aScript = [[NSAppleScript alloc] initWithSource:appleScriptSource];
NSAppleEventDescriptor *aDescriptor = [aScript executeAndReturnError:&anError];

NSLog (@"%@", aDescriptor);
[aScript release];

Thanks in advance for any help! :)

Answer 1

[[aDescriptor descriptorForKeyword:keyAEKeyData] stringValue]

Answer 2

That's a record, not a list. Try descriptorForKeyword:, passing the constant matching the four-character code you want. (The constants are declared in the Apple Events headers.)