Enum Maybe

pub enum Maybe<T> {
    Absent,
    Null,
    Value(T),
}

A serde value that distinguishes between null and missing values.

Note

When used as a field in a serializable type (although not needed for deserialization), the attribute #[serde(default, skip_serializing_if = "Maybe::is_absent")] must be placed on the field.

When used as a field in a deserialization, the attribute #[serde(default)] must be placed on the field.

OpenAPI

The override #[schema(nullable, value_type = Option<T>)] must be placed on the field.

Variants

Absent

The field is absent.

Null

The field is present but is set to null.

Value(T)

The field is present and is set to a value, T.

Implementations

impl<T> Maybe<T>

pub const fn is_absent(&self) -> bool

Returns true if the value is Absent.

pub fn map<U>(self, f: impl FnOnce(T) -> U) -> Maybe<U>

Maps the inner value of Maybe to a new value.

pub fn into_option_or_if_absent(self, fallback: Option<T>) -> Option<T>

Turns this into an Option, but if the value is Absent, the given fallback value is used instead.

pub fn into_option_or_if_absent_then( self, f: impl FnOnce() -> Option<T>, ) -> Option<T>

Turns this into an Option, but if the value is Absent, the given fallback function is called to produce a fallback value.

pub fn into_option(self) -> Option<T>

Turns this into an Option.

Trait Implementations

impl<T: Clone> Clone for Maybe<T>

fn clone(&self) -> Maybe<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for Maybe<T>

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

Formats the value using the given formatter.

impl<T> Default for Maybe<T>

fn default() -> Maybe<T>

Returns the “default value” for a type.

impl<'de, T> Deserialize<'de> for Maybe<T>

where T: Deserialize<'de>,

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<T> From<Maybe<T>> for Option<T>

fn from(maybe: Maybe<T>) -> Self

Converts to this type from the input type.

impl<T> From<Option<T>> for Maybe<T>

fn from(opt: Option<T>) -> Self

Converts to this type from the input type.

impl<T: Serialize> Serialize for Maybe<T>

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.