[swift-evolution] Would having "MyType.Protocol" to indicate a type's protocols mess anything up?

[Daryle Walker]

We have

	MyType.Type

to indicate the meta-type of a type. And

	MyProtocol.Protocol

to indicate the meta-type of a protocol. Would it be OK to add

	MyType.Protocol

to identify all the protocols MyType follows? The result would be like if each protocol was connected by “&”, or “Any” if the type doesn’t follow any protocols.

…

Woah, I realized that this could be a bigger than anticipated. A type can specify its protocols directly, or through extension(s). Heck, I do that in my Cocoa projects to segregate each aspect of a class. So I guess we have to allow the protocol list to include those imported via extensions.

…

Why do I want to do this? It’s part of my retype/strong-typedef/alternate-interface idea. I originally made the developer list each protocol to re-implment separately in the export list and the protocol list. But that would be tedious for a long list of protocols. So I’m thinking “why not have a way to specify all of the protocols at once.” But I’m not sure on the syntax, that’s why I’m asking here. Alternatives could be things like “#protocolof(MyType)”. Unless we already have this capability?…

(Having a retype that repeats all of the implementation type’s protocols is still useful. The types would have the same interface, but still don’t share function overloads.)

— 
Daryle Walker
Mac, Internet, and Video Game Junkie
darylew AT mac DOT com 

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