Initial Googling indicates that there's no built-in way to do regular expressions in an Objective-C Cocoa application.
So four questions:
Is that really true?
Are you kidding me?
Ok, then is there a nice open-source library you recommend?
What are ways to get close enough without importing a library, perhaps with the NSScanner class?
I noticed that as of iOS 4.0 Apple provides a NSRegularExpression class. Additionally, as of 10.7, the class is available under OS X.