[Proposal] Set literals

[vns]

@crontab

In any case, anything that can shorten the code without making it too cryptic <- and this is where it gets tricky of course, but anything that can make your code shorter is good unless proven otherwise, not the other way around.

BTW, as pointed in parallel thread, that is not what Swift aims for at all:

• Clarity is more important than brevity. Although Swift code can be compact, it is a non-goal to enable the smallest possible code with the fewest characters. Brevity in Swift code, where it occurs, is a side-effect of the strong type system and features that naturally reduce boilerplate.