How to write a multiline string in Swift?

How could I split a string over multiple lines such as below?

var text:String = "This is some text
                   over multiple lines"

Swift 4 includes support for multi-line string literals. In addition to newlines they can also contain unescaped quotes.

var text = """
    This is some text
    over multiple lines
    """

Older versions of Swift don't allow you to have a single literal over multiple lines but you can add literals together over multiple lines:

var text = "This is some text\n"
         + "over multiple lines\n"