Trying to define a custom NSCharacterSet with unicode characters in Swift

Question

I want to define in Swift an NSCharacterSet containing: [Ａ-Ｚ] (note the double-bytes, this is not [A-Z]).

What is the proper syntax to do that? The code below that I had working in Objectiv C doesn't seem to translate to Swift so easily.'

    NSRange alphaDoubleByteRange;
    NSMutableCharacterSet *alphaDoubleByteLetters;
    alphaDoubleByteRange.location = (unsigned int)[@"Ａ" characterAtIndex:0];
    alphaDoubleByteRange.length = 26;
    alphaDoubleByteLetters = [[NSMutableCharacterSet alloc] init];
    [alphaDoubleByteLetters formUnionWithCharacterSet:[NSCharacterSet characterSetWithRange:alphaDoubleByteRange]];
    // Now alphaDoubleByteLetters contains what I want.

Answer 1

You can create a character set from the range of the unicode scalar values:

let firstCode = Int("Ａ".unicodeScalars.first!.value)
let lastCode =  Int("Ｚ".unicodeScalars.first!.value)
let alphaDoubleByteRange = NSRange(location: firstCode, length: lastCode - firstCode + 1)
let alphaDoubleByteLetters = NSCharacterSet(range: alphaDoubleByteRange)

Alternatively, lookup the characters in a Unicode table and use the scalar values directly:

let firstCode = 0xFF21  // "Ａ"
let lastCode =  0xFF3A  // "Ｚ"
// ...