[swift-evolution] [Pitch] Introduce user-defined dynamically "callable" types

[Charles Srstka]

> On Nov 10, 2017, at 12:04 PM, Joe Groff via swift-evolution <swift-evolution at swift.org> wrote:
> 
> I don't like the idea of some calls having wildly different semantics from others; it's difficult enough to tell what exactly a call might be doing already. Since we also lack the more obvious static "Callable" protocol idea to give even well-typed call syntax to user-defined types, this also seems like it'd be easily abused for that purpose too.

We already have that though, with the Objective-C bridge. How is the proposed behavior here more wildly different than the semantics of non- at objc, @objc, and @objc dynamic calls?

Charles