Type & field constraints

Constraint decorators bound a field's value, and wcl check enforces them. They also attach to a type alias (type Name = TypeRef), in which case every field declared with that alias is validated against them — the constraint travels with the name.

Decorator	Constraint
@min(n)	Numeric value must be at least n
@max(n)	Numeric value must be at most n
@non_empty	The string or list value must not be empty

@min(1) @max(65535)
type Port = u16

@non_empty
type Name = utf8

type Service {
  name: Name        // rejects ""
  port: Port        // rejects 0u16 and 70000-ish values
}

- Records

- Schema & Decorators

- Fields & Blocks