Fields and their settings

A field's settings, such as generated:, unique: and on_delete:, go in a block after its type, one per line:

entity Todo {    id: Uuid    due_at: Instant?    created_at: Instant {        generated: Generated.on_create  // set once, when the record is created    }    updated_at: Instant {        generated: Generated.on_change  // set on create and on every change    }}

generated: makes a field that Jadpo sets from the operation's clock: Generated.on_create sets it once, when the record is created, and Generated.on_change sets it on create and on every change. A generated field is a required Instant. Code never assigns it, and it is never in an Input.

A field that may be empty is written T?, like due_at above. Only an Input has optional: and default:. A starting value that Jadpo sets, rather than the caller, is the lifecycle's initial: (Lifecycle).