I’ve managed to figure out how to implement wildmat patterns inside of Wombat. It turns out NSPredicate does in fact support regular expressions, as documented in Using Predicates. You simply use the MATCHES operator to specify a regular expression, as shown in a couple of examples in Apple’s documentation. It’s implemented using ICU’s Regular Expressions package, which provides much better documentation than Apple.
The gotcha to note is that the MATCHES operator does not compile down to SQL, so you can’t give it directly to Core Data. Instead you have to pull out all the entities then post-process the array using NSArray’s filteredArrayUsingPredicate: method. It works, but it’s not as efficient as it would be if it were compiled down to SQL.