Enum Nullable 

pub enum Nullable<T> {
    Null,
    Some(T),
}

Value that can be null.

Option is used throughout this crate for entries that may or may not be present. A JSON-LD entry can also be present with the explicit value null, which is meaningful: it unsets whatever the surrounding context inherited. Hence this separate type, so that Option<Nullable<T>> can tell an absent entry from an entry set to null.

Variants

Null

The null value.

Some(T)

Any other value.

Implementations

impl<T> Nullable<T>

pub fn is_null(&self) -> bool

Checks if the value is null.

pub fn is_some(&self) -> bool

Checks if the value is not null.

pub fn try_unwrap(self) -> Result<T, NullError>

Returns the inner value, or NullError if null.

Errors

Returns an error when the value is null.

pub fn as_ref(&self) -> Nullable<&T>

Converts &Nullable<T> into Nullable<&T>.

pub fn as_deref(&self) -> Nullable<&T::Target>

where T: Deref,

Converts &Nullable<T> into Nullable<&T::Target> by dereferencing the inner value.

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

Converts this value into an Option, mapping null to None.

pub fn map<F, U>(self, f: F) -> Nullable<U>

where F: FnOnce(T) -> U,

Maps the inner value with the given function, keeping null as null.

pub fn cast<U>(self) -> Nullable<U>

where T: Into<U>,

Converts the contained value, keeping null as null.

pub fn unwrap_or(self, default: T) -> T

Returns the contained value, or default if it is null.

pub fn unwrap_or_default(self) -> T

where T: Default,

Returns the contained value, or the default one if it is null.

impl<T: Clone> Nullable<&T>

pub fn cloned(&self) -> Nullable<T>

Clones the referenced inner value.

impl<T> Nullable<T>

pub fn optional<'de, D>(deserializer: D) -> Result<Option<Self>, D::Error>

where T: Deserialize<'de>, D: Deserializer<'de>,

Available on crate feature serde only.

Deserializes a Nullable<T> and wraps it in Some.

Meant as the deserialize_with of an Option<Nullable<T>> field that also carries #[serde(default)]: an absent entry then yields None, while an entry present with the value null yields Some(Nullable::Null). Serde’s own handling of Option would collapse both cases to None.

Errors

Returns the deserializer’s error when the value is neither absent, null, nor a valid T.

Trait Implementations

impl<T: Clone> Clone for Nullable<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: Copy> Copy for Nullable<T>

impl<T: Debug> Debug for Nullable<T>

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

Formats the value using the given formatter.

impl<'de, T: Deserialize<'de>> Deserialize<'de> for Nullable<T>

Available on crate feature serde only.

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

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<T: Display> Display for Nullable<T>

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

Formats the value using the given formatter.

impl<T: DisplayWithContext<V>, V> DisplayWithContext<V> for Nullable<T>

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

impl<T: Eq> Eq for Nullable<T>

impl<'a> From<Nullable<&'a TermDefinition>> for ExpandedRef<'a>

fn from(value: Nullable<&'a TermDefinition>) -> Self

Converts to this type from the input type.

impl<T> From<Option<T>> for Nullable<T>

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

Converts to this type from the input type.

impl<T> From<T> for Nullable<T>

fn from(value: T) -> Self

Converts to this type from the input type.

impl<T: Hash> Hash for Nullable<T>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<T: IntoJson> IntoJson for Nullable<T>

fn into_json(self) -> Value

Converts this value into JSON.

impl<T: Ord> Ord for Nullable<T>

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl<T: PartialEq> PartialEq for Nullable<T>

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

Equality operator ==.

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

Inequality operator !=.

impl<T: PartialOrd> PartialOrd for Nullable<T>

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl PrecomputeSize for Nullable<&Vocab>

fn pre_compute_size(&self, options: &Options, sizes: &mut Vec<Size>) -> Size

Computes the printed size of this value, appending the size of each nested array and object to sizes.

impl PrecomputeSize for Nullable<&TermDefinition>

fn pre_compute_size(&self, options: &Options, sizes: &mut Vec<Size>) -> Size

Computes the printed size of this value, appending the size of each nested array and object to sizes.

impl PrecomputeSize for Nullable<&Id>

fn pre_compute_size(&self, options: &Options, sizes: &mut Vec<Size>) -> Size

Computes the printed size of this value, appending the size of each nested array and object to sizes.

impl PrecomputeSize for Nullable<&Type>

fn pre_compute_size(&self, options: &Options, sizes: &mut Vec<Size>) -> Size

Computes the printed size of this value, appending the size of each nested array and object to sizes.

impl PrecomputeSize for Nullable<&Container>

fn pre_compute_size(&self, options: &Options, sizes: &mut Vec<Size>) -> Size

Computes the printed size of this value, appending the size of each nested array and object to sizes.

impl PrecomputeSize for Nullable<&IriRefBuf>

fn pre_compute_size(&self, _options: &Options, _sizes: &mut Vec<Size>) -> Size

Computes the printed size of this value, appending the size of each nested array and object to sizes.

impl PrecomputeSize for Nullable<IriRefBuf>

fn pre_compute_size(&self, _options: &Options, _sizes: &mut Vec<Size>) -> Size

Computes the printed size of this value, appending the size of each nested array and object to sizes.

impl PrecomputeSize for Nullable<bool>

fn pre_compute_size(&self, options: &Options, sizes: &mut Vec<Size>) -> Size

Computes the printed size of this value, appending the size of each nested array and object to sizes.

impl PrecomputeSize for Nullable<&LenientLangTagBuf>

fn pre_compute_size(&self, _options: &Options, _sizes: &mut Vec<Size>) -> Size

Computes the printed size of this value, appending the size of each nested array and object to sizes.

impl PrecomputeSize for Nullable<Direction>

fn pre_compute_size(&self, _options: &Options, _sizes: &mut Vec<Size>) -> Size

Computes the printed size of this value, appending the size of each nested array and object to sizes.

impl Print for Nullable<&Vocab>

fn fmt_with( &self, f: &mut Formatter<'_>, options: &Options, indent: usize, ) -> Result

Writes the value to f with the given options, starting at the given indentation level.

fn pretty_print(&self) -> Printed<'_, Self>

Print the value with Options::pretty options.

fn compact_print(&self) -> Printed<'_, Self>

Print the value with Options::compact options.

fn inline_print(&self) -> Printed<'_, Self>

Print the value with Options::inline options.

fn print_with(&self, options: Options) -> Printed<'_, Self>

Print the value with the given options.

impl Print for Nullable<&Id>

fn fmt_with( &self, f: &mut Formatter<'_>, options: &Options, indent: usize, ) -> Result

Writes the value to f with the given options, starting at the given indentation level.

fn pretty_print(&self) -> Printed<'_, Self>

Print the value with Options::pretty options.

fn compact_print(&self) -> Printed<'_, Self>

Print the value with Options::compact options.

fn inline_print(&self) -> Printed<'_, Self>

Print the value with Options::inline options.

fn print_with(&self, options: Options) -> Printed<'_, Self>

Print the value with the given options.

impl Print for Nullable<&Type>

fn fmt_with( &self, f: &mut Formatter<'_>, options: &Options, indent: usize, ) -> Result

Writes the value to f with the given options, starting at the given indentation level.

fn pretty_print(&self) -> Printed<'_, Self>

Print the value with Options::pretty options.

fn compact_print(&self) -> Printed<'_, Self>

Print the value with Options::compact options.

fn inline_print(&self) -> Printed<'_, Self>

Print the value with Options::inline options.

fn print_with(&self, options: Options) -> Printed<'_, Self>

Print the value with the given options.

impl Print for Nullable<&IriRefBuf>

fn fmt_with( &self, f: &mut Formatter<'_>, _options: &Options, _indent: usize, ) -> Result

Writes the value to f with the given options, starting at the given indentation level.

fn pretty_print(&self) -> Printed<'_, Self>

Print the value with Options::pretty options.

fn compact_print(&self) -> Printed<'_, Self>

Print the value with Options::compact options.

fn inline_print(&self) -> Printed<'_, Self>

Print the value with Options::inline options.

fn print_with(&self, options: Options) -> Printed<'_, Self>

Print the value with the given options.

impl Print for Nullable<IriRefBuf>

fn fmt_with( &self, f: &mut Formatter<'_>, _options: &Options, _indent: usize, ) -> Result

Writes the value to f with the given options, starting at the given indentation level.

fn pretty_print(&self) -> Printed<'_, Self>

Print the value with Options::pretty options.

fn compact_print(&self) -> Printed<'_, Self>

Print the value with Options::compact options.

fn inline_print(&self) -> Printed<'_, Self>

Print the value with Options::inline options.

fn print_with(&self, options: Options) -> Printed<'_, Self>

Print the value with the given options.

impl Print for Nullable<bool>

fn fmt_with( &self, f: &mut Formatter<'_>, options: &Options, indent: usize, ) -> Result

Writes the value to f with the given options, starting at the given indentation level.

fn pretty_print(&self) -> Printed<'_, Self>

Print the value with Options::pretty options.

fn compact_print(&self) -> Printed<'_, Self>

Print the value with Options::compact options.

fn inline_print(&self) -> Printed<'_, Self>

Print the value with Options::inline options.

fn print_with(&self, options: Options) -> Printed<'_, Self>

Print the value with the given options.

impl Print for Nullable<&LenientLangTagBuf>

fn fmt_with( &self, f: &mut Formatter<'_>, _options: &Options, _indent: usize, ) -> Result

Writes the value to f with the given options, starting at the given indentation level.

fn pretty_print(&self) -> Printed<'_, Self>

Print the value with Options::pretty options.

fn compact_print(&self) -> Printed<'_, Self>

Print the value with Options::compact options.

fn inline_print(&self) -> Printed<'_, Self>

Print the value with Options::inline options.

fn print_with(&self, options: Options) -> Printed<'_, Self>

Print the value with the given options.

impl Print for Nullable<Direction>

fn fmt_with( &self, f: &mut Formatter<'_>, _options: &Options, _indent: usize, ) -> Result

Writes the value to f with the given options, starting at the given indentation level.

fn pretty_print(&self) -> Printed<'_, Self>

Print the value with Options::pretty options.

fn compact_print(&self) -> Printed<'_, Self>

Print the value with Options::compact options.

fn inline_print(&self) -> Printed<'_, Self>

Print the value with Options::inline options.

fn print_with(&self, options: Options) -> Printed<'_, Self>

Print the value with the given options.

impl PrintWithSize for Nullable<&TermDefinition>

fn fmt_with_size( &self, f: &mut Formatter<'_>, options: &Options, indent: usize, sizes: &[Size], index: &mut usize, ) -> Result

Writes the value to f, taking its layout from sizes[*index].

impl PrintWithSize for Nullable<&Container>

fn fmt_with_size( &self, f: &mut Formatter<'_>, options: &Options, indent: usize, sizes: &[Size], index: &mut usize, ) -> Result

Writes the value to f, taking its layout from sizes[*index].

impl<T: Serialize> Serialize for Nullable<T>

Available on crate feature serde only.

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

where S: Serializer,

Serialize this value into the given Serde serializer.

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

impl<T: TryFromJson> TryFromJson for Nullable<T>

type Error = <T as TryFromJson>::Error

Error raised when the JSON value does not describe a valid Self.

fn try_from_json(value: &Value) -> Result<Self, Self::Error>

Builds a value of this type from the given JSON value.