Sensible Swift snippets

String+Sensible.swift

extension String {
    var length: Int {
        return self.lengthOfBytes(using: .utf8)
    }
    
    subscript(index: String.Index) -> Character {
        get { return self.characters[index] }
        set {
            self.remove(at: index)
            self.insert(newValue, at: index)
        }
    }
    
    subscript(range: Range<Index>) -> String {
        get { return String(self[range]) }
        set { self.replaceSubrange(range, with: newValue) }
    }
    
    func getIndex(_ v: Int) -> Index {
        return self.index(startIndex, offsetBy: v)
    }
    
    func getIndexRange(_ r: CountableRange<Int>) -> Range<Index> {
        let start = getIndex(r.lowerBound)
        let end = index(start, offsetBy:  r.count)
        return start..<end
    }
    
    subscript(index: Int) -> Character {
        get { return self[getIndex(index)]     }
        set { self[getIndex(index)] = newValue }
    }
    
    subscript(range: CountableRange<Int>) -> String {
        get { return self[getIndexRange(range)]     }
        set { self[getIndexRange(range)] = newValue }
    }
    
    subscript(range: NSRange) -> String {
        get { return self[CountableRange<Int>(range)!]     }
        set { self[CountableRange<Int>(range)!] = newValue }
    }
}