[swift-evolution] Language syntax proposal - shorthand for super invocations

[Radosław Pietruszewski]

I want to say +1.

Ruby does this and it works really nicely.  While not a big deal in simple cases, when a method has lots of arguments, it’s just really noisy.

There’s a problem though. If `super` means both “call the superclass’s implementation of this method”, and “the superclass”, there’s a potential for ambiguity.

Say:

> override var widgetCount: Int {
>     return super.widgetCount + 5
> }

And:

extension Int {
    var widgetCount: Int { return 10 }
}

Does super.widgetCount call the superclass’s `widgetCount`, or does it call the superclass’s implementation of the same getter, then call `widgetCount` on the returned Int?

— Radek

> On 09 Feb 2016, at 06:31, Petroules Jake via swift-evolution <swift-evolution at swift.org> wrote:
> 
> Hello,
> 
> I have a language syntax proposal. I've read the Swift evolution guidelines and hopefully this is the proper way to start. So, my proposal is:
> 
> Permit a shorthand syntax for invoking the supertype implementation of a property or function. A single statement 'super' is equivalent to invoking the supertype implementation, forwarding the arguments unchanged, and returning the result. For example, the following samples:
> 
> override func mouseEntered(theEvent: NSEvent) {
>     super
>     handleMouseEvent(theEvent)
> }
> 
> override func specialValue(key: String) -> Int {
>     return super + 1
> }
> 
> override var widgetCount: Int {
>     return super + 5
> }
> 
> are exactly equivalent to the following samples:
> 
> override func mouseEntered(theEvent: NSEvent) {
>     super.mouseEntered(theEvent)
>     handleMouseEvent(theEvent)
> }
> 
> override func specialValue(key: String) -> Int {
>     return super.specialValue(key) + 1
> }
> 
> override var widgetCount: Int {
>     return super.widgetCount + 5
> }
> 
> Alternatives/complementary ideas:
> 
> - Require `super()` or `super(...)` syntax for invocations which are function calls, for consistency with other function calls in the language and/or to indicate that arguments are forwarded
> 
> Looking forward to your feedback.
> 
> Thanks!
> -- 
> Jake Petroules - jake.petroules at theqtcompany.com <mailto:jake.petroules at theqtcompany.com>
> Consulting Services Engineer - The Qt Company
> 
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