Struct Optional

pub struct Optional<T>(/* private fields */);

A datatype that represents an optional value.

Trait Implementations

impl<T: Clone> Clone for Optional<T>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Datatype for Optional<BigInt>

type Inner = Optional<BigInt>

type Error = <Optional<BigInt> as FromStr>::Err

fn validate( input: Optional<BigInt>, ) -> Result<Self, <Optional<BigInt> as FromStr>::Err>

Validate the input and return the datatype.

fn attributes() -> Vec<(&'static str, Attribute)>

Return the HTML attributes for the datatype that should be added to an input field.

impl Datatype for Optional<Date>

type Inner = Optional<Date>

type Error = <Optional<Date> as FromStr>::Err

fn validate( input: Optional<Date>, ) -> Result<Self, <Optional<Date> as FromStr>::Err>

Validate the input and return the datatype.

fn attributes() -> Vec<(&'static str, Attribute)>

Return the HTML attributes for the datatype that should be added to an input field.

impl Datatype for Optional<DateTime>

type Inner = Optional<DateTime>

type Error = <Optional<DateTime> as FromStr>::Err

fn validate( input: Optional<DateTime>, ) -> Result<Self, <Optional<DateTime> as FromStr>::Err>

Validate the input and return the datatype.

fn attributes() -> Vec<(&'static str, Attribute)>

Return the HTML attributes for the datatype that should be added to an input field.

impl Datatype for Optional<BigRational>

type Inner = Optional<Ratio<BigInt>>

type Error = <Optional<Ratio<BigInt>> as FromStr>::Err

fn validate( input: Optional<BigRational>, ) -> Result<Self, <Optional<BigRational> as FromStr>::Err>

Validate the input and return the datatype.

fn attributes() -> Vec<(&'static str, Attribute)>

Return the HTML attributes for the datatype that should be added to an input field.

impl Datatype for Optional<Time>

type Inner = Optional<Time>

type Error = <Optional<Time> as FromStr>::Err

fn validate( input: Optional<Time>, ) -> Result<Self, <Optional<Time> as FromStr>::Err>

Validate the input and return the datatype.

fn attributes() -> Vec<(&'static str, Attribute)>

Return the HTML attributes for the datatype that should be added to an input field.

impl Datatype for Optional<i128>

type Inner = Optional<i128>

type Error = <Optional<i128> as FromStr>::Err

fn validate( input: Optional<i128>, ) -> Result<Self, <Optional<i128> as FromStr>::Err>

Validate the input and return the datatype.

fn attributes() -> Vec<(&'static str, Attribute)>

Return the HTML attributes for the datatype that should be added to an input field.

impl Datatype for Optional<i16>

type Inner = Optional<i16>

type Error = <Optional<i16> as FromStr>::Err

fn validate( input: Optional<i16>, ) -> Result<Self, <Optional<i16> as FromStr>::Err>

Validate the input and return the datatype.

fn attributes() -> Vec<(&'static str, Attribute)>

Return the HTML attributes for the datatype that should be added to an input field.

impl Datatype for Optional<i32>

type Inner = Optional<i32>

type Error = <Optional<i32> as FromStr>::Err

fn validate( input: Optional<i32>, ) -> Result<Self, <Optional<i32> as FromStr>::Err>

Validate the input and return the datatype.

fn attributes() -> Vec<(&'static str, Attribute)>

Return the HTML attributes for the datatype that should be added to an input field.

impl Datatype for Optional<i64>

type Inner = Optional<i64>

type Error = <Optional<i64> as FromStr>::Err

fn validate( input: Optional<i64>, ) -> Result<Self, <Optional<i64> as FromStr>::Err>

Validate the input and return the datatype.

fn attributes() -> Vec<(&'static str, Attribute)>

Return the HTML attributes for the datatype that should be added to an input field.

impl Datatype for Optional<i8>

type Inner = Optional<i8>

type Error = <Optional<i8> as FromStr>::Err

fn validate(input: Optional<i8>) -> Result<Self, <Optional<i8> as FromStr>::Err>

Validate the input and return the datatype.

fn attributes() -> Vec<(&'static str, Attribute)>

Return the HTML attributes for the datatype that should be added to an input field.

impl Datatype for Optional<u128>

type Inner = Optional<u128>

type Error = <Optional<u128> as FromStr>::Err

fn validate( input: Optional<u128>, ) -> Result<Self, <Optional<u128> as FromStr>::Err>

Validate the input and return the datatype.

fn attributes() -> Vec<(&'static str, Attribute)>

Return the HTML attributes for the datatype that should be added to an input field.

impl Datatype for Optional<u16>

type Inner = Optional<u16>

type Error = <Optional<u16> as FromStr>::Err

fn validate( input: Optional<u16>, ) -> Result<Self, <Optional<u16> as FromStr>::Err>

Validate the input and return the datatype.

fn attributes() -> Vec<(&'static str, Attribute)>

Return the HTML attributes for the datatype that should be added to an input field.

impl Datatype for Optional<u32>

type Inner = Optional<u32>

type Error = <Optional<u32> as FromStr>::Err

fn validate( input: Optional<u32>, ) -> Result<Self, <Optional<u32> as FromStr>::Err>

Validate the input and return the datatype.

fn attributes() -> Vec<(&'static str, Attribute)>

Return the HTML attributes for the datatype that should be added to an input field.

impl Datatype for Optional<u64>

type Inner = Optional<u64>

type Error = <Optional<u64> as FromStr>::Err

fn validate( input: Optional<u64>, ) -> Result<Self, <Optional<u64> as FromStr>::Err>

Validate the input and return the datatype.

fn attributes() -> Vec<(&'static str, Attribute)>

Return the HTML attributes for the datatype that should be added to an input field.

impl Datatype for Optional<u8>

type Inner = Optional<u8>

type Error = <Optional<u8> as FromStr>::Err

fn validate(input: Optional<u8>) -> Result<Self, <Optional<u8> as FromStr>::Err>

Validate the input and return the datatype.

fn attributes() -> Vec<(&'static str, Attribute)>

Return the HTML attributes for the datatype that should be added to an input field.

impl<T: Debug> Debug for Optional<T>

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

Formats the value using the given formatter.

impl<T: Default> Default for Optional<T>

fn default() -> Optional<T>

Returns the “default value” for a type.

impl<T> Display for Optional<T>

where T: Display,

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

Formats the value using the given formatter.

impl<T> FromStr for Optional<T>

where T: FromStr,

type Err = <T as FromStr>::Err

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type.

impl<T: Hash> Hash for Optional<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: Ord> Ord for Optional<T>

fn cmp(&self, other: &Optional<T>) -> 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.

impl<T: PartialEq> PartialEq for Optional<T>

fn eq(&self, other: &Optional<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T: PartialOrd> PartialOrd for Optional<T>

fn partial_cmp(&self, other: &Optional<T>) -> 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<T: Eq> Eq for Optional<T>

impl<T> StructuralPartialEq for Optional<T>