What is the replacement for isDigit() for characters in Swift?

Question

As mentioned in this post, before Xcode 6 Beta 4, one could use c.isDigit() and c.isAlpha() to find if c : Character was a digit or al

Answer 1

The "problem" is that a Swift character does not directly correspond to a Unicode code point, but represents an "extended grapheme cluster" which can consist of multiple Unicode scalars. For example

let c : Character = "