Act 3, scene 12: Invariants plus rules: a domain-specific language

Scene 12: Invariants plus rules: a domain-specific language

That gives two things to name. The domain invariants are drawn from the knowledge graph and shared by every customer. The business rules differ for each customer. Together, the invariants and the business rules make a domain-specific language. The invariants are its vocabulary, and its grammar says how business rules may combine them: which parts may vary, what values they admit, and which combinations are legal. The multi-tenancy line moves down to sit on the invariants. Below it, shared by every tenant, are the invariants, a compiler for the language, the data platform and the infrastructure. Above the line, per customer, are onboarding, the interface, and each customer's business rules, written in the language. Moving the line down gives up some of the original sharing, which is affordable once the per-customer part is cheap to produce. That leaves one question. Who writes the business rules?