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swiftoperatorsinfix-operator

How to use ** for exponents using @infix func **( )?

I want to use ** to overload an exponent function. I works if I use something like "^" but the python way of doing is ** and I would like to use that with Swift. Any way to do that?

error: Operator implementation without matching operator declaration

@infix func ** (num: Double, power: Double) -> Double{
    return pow(num, power)
}

println(8.0**3.0) // Does not work
Solution

  • You need to declare the operator before defining the function, as follows:

    In Swift 2:

    import Darwin

infix operator ** {}

func ** (num: Double, power: Double) -> Double {
    return pow(num, power)
}

println(8.0 ** 3.0) // works

    In Swift 3:

    import Darwin

infix operator **

func ** (num: Double, power: Double) -> Double {
    return pow(num, power)
}

print(8.0 ** 3.0) // works