Enum Outcome 

pub enum Outcome<T> {
    Determinate(T),
    Indeterminate(Indeterminacy),
}

A value, or the reason there is none.

There is deliberately no Deref and no accessor that returns a value for the indeterminate case: the way to a number goes through a match, Outcome::value or Outcome::into_result, each of which says what happens otherwise.

Variants

Determinate(T)

A defensible answer.

Indeterminate(Indeterminacy)

No defensible answer exists.

Implementations

impl<T> Outcome<T>

pub const fn is_determinate(&self) -> bool

Returns true when there is an answer.

pub const fn value(&self) -> Option<&T>

The answer, if there is one.

pub const fn indeterminacy(&self) -> Option<&Indeterminacy>

The reason there is no answer, if there is none.

pub fn into_result(self) -> Result<T, Indeterminacy>

The answer, or the reason it is missing.

Errors

Returns the Indeterminacy when no defensible answer exists.

pub const fn as_result(&self) -> Result<&T, &Indeterminacy>

Borrows the answer, or the reason it is missing.

Errors

Returns the Indeterminacy when no defensible answer exists.

pub fn map<U>(self, transform: impl FnOnce(T) -> U) -> Outcome<U>

Transforms the answer and leaves a refusal as it is.

Trait Implementations

impl<T: Clone> Clone for Outcome<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for Outcome<T>

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

Formats the value using the given formatter.

impl<T: Eq> Eq for Outcome<T>

impl<T: PartialEq> PartialEq for Outcome<T>

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl<T: PartialEq> StructuralPartialEq for Outcome<T>