Cocoa: Testing to find if an NSString is immutable or mutable?

Question

This produces an immutable string object:

NSString* myStringA = @\"A\";  //CORRECTED FROM: NSMutableString* myStringA = @\"A\";

This produc

Answer 1

There's no (documented) way to determine if a string is mutable at runtime or not.

You would expect one of the following would work, but none of them work:

[[s class] isKindOfClass:[NSMutableString class]]; // always returns false
[s isMemberOfClass:[NSMutableString class]]; // always returns false
[s respondsToSelector:@selector(appendString)]; // always returns true

More info here, although it doesn't help you with the problem:

http://www.cocoabuilder.com/archive/cocoa/111173-mutability.html