Enum Opt 

pub enum Opt {
    Optional,
    Essential,
}

Optionality of a path part, i.e. whether ? is present.

For example, [] | .a fails with an error, while [] | .a? returns nothing. By default, path parts are essential, meaning that they fail. Annotating them with ? makes them optional.

Variants

Optional

Return nothing if the input cannot be accessed with the path

Essential

Fail if the input cannot be accessed with the path

Implementations

impl Opt

pub fn fail<T, E>(self, x: T, f: impl FnOnce(T) -> E) -> Result<T, E>

If self is optional, return x, else fail with f(x).

Trait Implementations

impl Clone for Opt

fn clone(&self) -> Opt

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Opt

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Copy for Opt