Runtime support across platforms

Like most other people, I’m here for the cross platform language support, but I’m scratching my head a little wondering where the line is drawn between the language and the platform.

In particular, I’d like to use the calls exposed in the Objective C runtime, but only if I can use them on all platforms.

https://developer.apple.com/library/mac/documentation/Cocoa/Reference/ObjCRuntimeRef/index.html

Are these implemented as a part of the Silver language runtime or are they strictly Cocoa?

The Cocoa/Objective-C runtime APIs will only be available on Cocoa. We’re not porting Cocoa itself over, just the language — on .NET and Java, Swift uses those runtimes, not the Objective-C one.