Swift: Check if first character of String is ASCII or a letter with an accent

Question

In Swift, how do I check whether the first character of a String is ASCII or a letter with an accent? Wider characters, like emoticons & logograms, don't count.

I'm trying to copy how the iPhone Messages app shows a person's initials beside their message in a group chat. But, it doesn't include an initial if it's an emoticon or a Chinese character for example.

I see decomposableCharacterSet & nonBaseCharacterSet, but I'm not sure if those are what I want.

Answer 1

There are many Unicode Character with an accent. Is this for you a character with an accent?

Ê Ð Ï Ḝ Ṹ é⃝

---

In Unicode there are combined characters, which are two unicode characters as one:

let eAcute: Character = "\u{E9}"                         // é
let combinedEAcute: Character = "\u{65}\u{301}"          // e followed by ́
// eAcute is é, combinedEAcute is é

For Swift the Character is the same!

Good reference is here.

---

If you want to know the CodeUnit of the Characters in the String, you can use the utf8 or utf16 property. They are different!

let characterString: String = "abc"
for character in characterString.utf8 {
    print("\(character) ")
}
// output are decimal numbers: 97 98 99 
// output of only é: 195 169, used the combined é

Then you could check for ASCII alphabet A-Z as 65-90 and a-z as 97-122. And then check for the standard accent grave and acute À 192 Á 193 È 200 É 201 à 224 á 225 è 232 é 233 ... and the combined ones and everything you like.

But there are symbols that look like a latin letter with accent, but doesn't have the same meaning!

You should make sure, that only these characters are accepted, that you want with the correct linguistic meaning.