outrun/outrun-core/lib/option.run

use Any
use Boolean
use Option
use Outrun.Core.Some, as: Some
use Outrun.Core.None, as: None

```doc
# Option

The optional type.

An option is anything that an optionally provide a value.  Most commonly this will be in the shape of the `Outrun.Core.Option` enum.
```

protocol Option, as: do
  ```doc
  Returns true if the `Option` can provide a value, false otherwise.

  Must be implemented.
  ```
  def some?(option: Self): Boolean

  ```doc
  Returns the value of the option, or raises an error if it can not.

  Must be implemented.
  ```
  def unwrap(option: Self): Any

  ```doc
  Returns true if the `Option` cannot provide a value, false otherwise.
  ```
  def none?(option: Self): Boolean, as: !some?(option)

  ```doc
  Create a new "some" value using the default some type.
  ```
  defs some(value: Any): Option, as: Some.new(value)

  ```doc
  Create a new "none" value using the default none type.
  ```
  defs none(): Option, as: None.new()
end