List of types

You write the program body as a class (the shape of a program). Otherwise, when you define your own type, you use one of struct, record, enum, interface, or union. Apart from a static class that holds methods (Extension methods), class is supported for declaration only; creating one or reading and writing it errors (struct and record).

Pages per type

Page	Forms that compile	Forms that don’t compile	Contents
Primitive types	5	1
Arrays	53	19	An array holds a fixed number of values of the same type, decided in advance.
Enums	7	4
struct and record	36	9
Tuples	10	4
union (sum type)	8	4	A union is a base declared with abstract record, together with the record types that inherit from it.
Generics	29	11
Interfaces	23	9