What is NSConcreteMutableData?

FROM : Frederick C. Lee
DATE : Fri Nov 26 20:17:31 2004

Greetings:
   I'm deciphering a NSArrayController example that has a NSTextView
field mapped to the key 'xnotes'.    The example saves/reads data just
fine.    So I go into the debugger to explore the data array the is
read/write from disk.  The following is what I've found for the
'xnotes' data key for the NSTextView:

(gdb) po [[[toDos objectAtIndex:1] objectForKey:@"xnotes"] class]
NSConcreteMutableData
(gdb)


I tried to read the data using [xnotes string] but didn't work.  The
object didn't recognize the method.  So I asked the gdb to reveal the
class to be: 'NSConcreteMutableData' which appears to be an oxymoron.

Any ideas?

Ric.