CASSANDRA-6875 we need to be able to talk about tuples values and types (for prepared variables). Since we need it there, clients will need to support them anyway and so I think it would be a lot cleaner to start supporting those more generally. Besides, having tuples is a relatively simple and natural extension to what we have. I'll note in particular that tuple have a close relationship to user type in the sense that a tuple will be really just like an anonymous with no name for the fields and in particular a tuple value will be the same than a user type value.
The syntax would simply look like that:
We can also add projections in selects if we want:
but that can come later (after all, we still don't have projections for collections and it's not a big deal).