What Is a Rulebook?

A rulebook is one file holding two kinds of thing: facts you type, and rules that work things out from those facts. This is a real run in an empty folder. effortless -init writes a rulebook that already computes, one command watches it, and from then on there is no build step at all. Rename Bob to Bobby and a greeting rewrites itself, in another table. Change the greeting formula and every row and every venue follows. Nobody types a derived value, ever.