See proceedings e.g. dblp.org/db/conf/icail/… and link.springer.com/book/10.1007/9…
1: "Great, I'll have an espresso."
2: "Vanilla ice cream for me."
Waiter: "You misunderstand. The only thing available at this point is an affogato."
[ foo, bar, baz ]
In L4, the syntax for lists can be
[ foo, bar & baz ]
[ foo, bar && baz ]
[ foo, bar | baz ]
representing "distributive and", "conjunctive and", and "exclusive or". (This is not yet finalized.)
(Hence isomorphism.)
and to the #RulesAsCode community for sharing your work-in-progress – I am particularly excited about the work happening in NZ, tip of the hat to @nardwebster and @verbman.
If you're doing an RaC project please let me know, maybe I can help?