ios - Type 'String.Index' does not conform protocol 'IntegerLiteralConvertible'

Question

With Beta 3 all worked fine, now I get a strange error, and I have no clue how to fix it. Tried all the solutions for similiar problems.

Here is my code:

if !name.isEmpty {
        var splitted: [String] = name.componentsSeparatedByString(" ")

        for curPart in splitted {
            if !curPart.isEmpty {
                acronym += curPart.substringToIndex(1) //Error
            }
        }
        if (acronym as NSString).length > 2 {
            acronym = acronym.substringToIndex(2) //Error
        }
    }

Both marked lines gave me the same error:

Type 'String.Index' does not conform protocol 'IntegerLiteralConvertible'

Can someone help me? Or is Beta 4 bugged? Thanks!

Answer 1

In beta 4, Swift's String.Index handling changed yet again -- you now can't supply an Int when a String.Index is expected. The way to handle it is by creating the String.Index you need using the advance method:

if !name.isEmpty {
    var splitted: [String] = name.componentsSeparatedByString(" ")

    for curPart in splitted {
        if !curPart.isEmpty {
            acronym += curPart.substringToIndex(advance(curPart.startIndex, 1))
        }
    }
    if countElements(acronym) > 2 {
        acronym = acronym.substringToIndex(advance(acronym.startIndex, 2))
    }
}

This is all based on making sure Unicode strings are handled properly - since different Unicode characters can have different sizes, pure integer indexing would hide the fact that Strings aren't random access.