optional

func As ¶

func As[T any, X any](
	x Optional[X],
) Optional[T]

As applies a type assertion to v. It returns an empty optional value if the type assertion fails.

func AtIndex ¶

func AtIndex[E any, S ~[]E](s S, i int) Optional[E]

AtIndex returns the element at index i in s, or None if i is out of bounds.

func First ¶

func First[E any, S ~[]E](s S) Optional[E]

First returns the first element in s, or None if s is empty.

func Key ¶

func Key[K comparable, V any, M ~map[K]V](m M, k K) Optional[V]

Key returns the value associated with key k in map m, or None if k is not present in m.

func Last ¶

func Last[E any, S ~[]E](s S) Optional[E]

Last returns the last element in s, or None if s is empty.

func None ¶

func None[T any]() Optional[T]

None returns an Optional[T] that does not contain a value.

func Some ¶

func Some[T any](v T) Optional[T]

Some returns an Optional[T] that contains the given value.

func Transform ¶

func Transform[T, X any](
	x Optional[X],
	fn func(X) T,
) Optional[T]

Transform applies a transformation to v, returning a new optional value that contains the result of the function.

If v's value is not present, the returned optional value will also not contain a value.

func TryTransform ¶

func TryTransform[T, X any](
	x Optional[X],
	fn func(X) (T, bool),
) Optional[T]

TryTransform applies a transformation to v, returning a new optional value that contains the result of the function.

If v's value is not present, the returned optional value will also not contain a value.