System.String Extension

property Chars[aIndex: Index]: Char read;

Char Chars[Index aIndex] { get; }

subscript Chars(_ aIndex: Index) -> Char { get{} }

ReadOnly Property Chars(aIndex As Index) As Char

property Chars[aRange: Range]: not nullable String read;

String! Chars[Range aRange] { get; }

subscript Chars(_ aRange: Range) -> String { get{} }

ReadOnly Property Chars(aRange As Range) As String

method Substring(aRange: Range): not nullable String

String! Substring(Range aRange)

func Substring(_ aRange: Range) -> String

Function Substring(aRange As Range) As String