Swift's generalCategory agrees with the Unicode standard everywhere except one codepoint: U+F8FF, which Apple's ICU refuses to classify as private-use (\p{Co}=n .. in XSD regex lingo).
Because U+F8FF is the Apple logo.
ICU regex also breaks with a{2147483647} .. 2147483647 is Int32.max. Maybe someday we'll have BigInt support here. ![]()