Scalars

Primitive types (String, Boolean, Integer, Long, Double, DateTime) may be declared and reused via a scalar declaration.

scalar <name> extends <primitive Concerto type> 
   <optional primitive Concerto type meta data>

Example:

namespace org.acme.hr@1.0.0
scalar SSN extends String default="000-00-0000" regex=/\d{3}-\d{2}-\{4}+/

concept Person identified by ssn {
    o SSN ssn
    o String givenName
}

Scalars may be imported from external namespaces in a manner similar to other imports.