Proposal: =? operator

I would like to have a built in =? operator which only assigns if the rhs is non-nil. If the rhs is nil, then it would do nothing.

I can make it myself (and have for my own projects), but I make a lot of frameworks and custom controls, and I don't want to unexpectedly make custom operators in other people's code base.

I use this fairly often, and one of the main areas where it comes in handy is in NSCoding.

With the =? operator

required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
     
        color =? aDecoder.decodeObjectForKey("color") as? UIColor
        borderWidth =? aDecoder.decodeObjectForKey("borderWidth") as? CGFloat
        borderColor =? aDecoder.decodeObjectForKey("borderColor") as? UIColor
     
        commonSetup()
}

As you can see, if a coded object has been stored (as the expected type), then it updates the default value. If it has not been stored, then it leaves it at the current/default value.

Without the =? operator, I have to recreate the defaults (which can get out-of-sync)

required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
     
        color = aDecoder.decodeObjectForKey("color") as? UIColor ?? UIColor.blackColor()
        borderWidth = aDecoder.decodeObjectForKey("borderWidth") as? CGFloat ?? 1.0
        borderColor = aDecoder.decodeObjectForKey("borderColor") as? UIColor ?? UIColor.blackColor()
     
        commonSetup()
}