It feels to me like there's plenty of design space to explore. Sure, it's possible to view "selection" as a basic building block, but even that is insufficientl

It feels to me like there's plenty of design space to explore. Sure, it's possible to view "selection" as a basic building block, but even that is insufficiently precise IMO. There's a reason that Javascript provides all of Promise.any and Promise.all and Promise.allSettled and Promise.race. Selection isn't just a single building block, it's an entire family of building blocks with distinct semantics.