+[NSString stringWithString:] -- what's the point?

Question

As NSString strings are immutable, what is the value of the stringWithString: class method?

I get the utility when used with NSMutableString, I just didn't see the utility with the NSString class.

Answer 1

You might have a NSMutableString (or some home-grown NSString subclass) that you want to duplicate.

NSMutableString *buffer = [NSMutableString string];
// do something with buffer
NSString *immutableStringToKeepAround = [NSString stringWithString:buffer];

Of course, you can also just make a copy:

NSMutableString *buffer = [NSMutableString string];
// do something with buffer
NSString *immutableStringToKeepAround = [[buffer copy] autorelease];

but you own the copy and must release or autorelease it.