# Enumerations

Enumerations are sum types.

## Syntax

An enumeration must have at least one type member.

```
enum <name>
    -- records or objects...
end enum
```

## Objects

An _object_ is a special type of singleton. Much like the `()` type, each object
is an instance of itself (and the only instance of itself). Objects are used to
represent enumeration cases that do not have any inputs.

## Example: The Option Type

```
given A
enum Option
    given A
    record Some (value: A)
    object None
end enum

given A
fn some: (a: A) => Some[A]
    Some (a)
end fn
```

## Example: The Either Type

```
given L, R
enum Either
    given L
    record Left (value: L)

    given R
    record Right (value: R)
end enum

given L
fn left: (left: L) => Either[L, Nothing]
    Left(left)
end fn

given R
fn right: (right: R) => Either[Nothing, R]
    Right(right)
end fn
```