outrun/lib/result.run

```doc
# Result

The result type.

A result is anything that either succeeds, resulting in a value, or fails resulting in an error.
```

protocol Result, as: do
  ```doc
  Returns true if the result is successful.

  Must be implemented.
  ```
  def okay?(self: Self): Boolean

  ```doc
  Returns true if the result is an error.
  ```
  def error?(self: Self): Boolean, as: !okay?(self)

  ```doc
  Returns the value of the result on success.

  If the result contains an `Ok` value, then the inner value will be returned.
  Implementations must raise an error on failure.
  ```
  def unwrap(self: Self): Any

  ```doc
  Returns the error on failure.

  If the result contains an `Error` value then it will be returned.
  Implementations must raise an error on success.
  ```
  def unwrap_error(self: Self): Error

  ```doc
  Creates a new successful result from a value.
  ```
  defs okay(value: Any): Result, as: Outrun.Core.Okay.new(value)

  ```doc
  Creates a new unsuccessful result from an error.
  ```
  defs error(error: Error): Result, as: Outrun.Core.Error.new(error)
end