How to customize ternary operators in Swift

Question

I know how to customize binary operators, like this

infix operator ** { associativity left precedence 170 }
func ** (left: Double, right: Double) -> Doubl         


        

Answer 1

A "true" ternary operator such as _ ? _ : _ requires language support. Swift allows creating and customizing only unary and binary operators.

You can use the technique in @NateCook's answer to make a pair of binary operators which together work like a ternary operator, but they're still independent binary operators -- you can use either on its own. (By contrast, _ ? _ : _ is only a ternary operator; _ ? _ and _ : _ can't be used individually.)

Of course, why stop there? You could chain more binary operators to create quaternary operators, and so on. For extra credit, try making yourself an extended spaceship operator:

let c: String = a <=> b
    |<| "a < b"
    |=| "a = b"
    |>| "a > b"

(...but please do this as an academic exercise only, or anyone else who works with code you write will hate you.)