Type Hierarchy:

- Anything
  - Null

Direct Known Subclasses: null
All Known Subtypes Hierarchy

- Null
  - null

The type of the `null` value. Any union type of form `Null|T` is considered an optional type, whose values include `null`. Any type of this form may be written as `T?` for convenience.

The `if (exists ... )` construct, or, alternatively, the `assert (exists ...)` construct, may be used to narrow an optional type to a definite type, that is, a subtype of `Object`:

    String? firstArg = process.arguments.first;
    if (exists firstArg) {
        print("hello " + firstArg);
    }

The `else` operator evaluates its second operand if and only if its first operand is `null`:

    String name = process.arguments.first else "world";

The `then` operator evaluates its second operand when its first operand evaluates to `true`, and to `null` otherwise:

    Float? diff = x>=y then x-y;

By: Gavin
See also: null

Initializer
Null()