package ucontainer

// Option can either hold a value, or nothing.
type Option[T any] struct {
	value T
	exists bool
}

// O creates a new option with the specified value.
func O[T any] (value T) Option[T] {
	return Option[T] {
		value: value,
		exists: true,
	}
}

// Void returns an option with no value.
func Void[T any] () Option[T] {
	return Option[T] { }
}

// Exists returns if the value is currently set.
func (option Option[T]) Exists () bool {
	return option.exists
}

// Value returns the value and true if the value exists. If not, it returns the
// zero value and false.
func (option Option[T]) Value () (T, bool) {
	return option.value, option.exists
}

// Default returns the value if it exists, and the specified default value
// otherwise.
func (option Option[T]) Default(defaul T) T {
	if value, ok := option.Value(); ok {
		return value
	}
	return defaul
}