How can I change the textual representation displayed for a type in Swift?

Question

How can I modify the textual output that gets displayed in string interpolation?

The Printable protocol looks the most obvious but it\'s ignored in both

Answer 1

As an alternative in Swift 5+ you can extend the String.StringInterpolation

struct Point {
    var x : Int
    var y : Int
}

extension String.StringInterpolation {
    mutating func appendInterpolation(_ value: Point) {
        appendInterpolation("\(value.x):\(value.y)")
    }
}

This will change the value for print("\(p)") but not for print(p) - which will still use the description