Enum Optional 

pub enum Optional<T: Parsable> {
    Some(T),
    None,
}

Variants

Some(T)

None

Implementations

impl<T: Parsable> Optional<T>

pub fn is_none(&self) -> bool

pub fn is_some(&self) -> bool

Trait Implementations

impl<T: Clone + Parsable> 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<T: Debug + Parsable> Debug for Optional<T>

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

Formats the value using the given formatter.

impl<T: Parsable> Display for Optional<T>

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

Formats the value using the given formatter.

impl<T: Parsable> From<Option<T>> for Optional<T>

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

Converts to this type from the input type.

impl<T: Parsable> From<Optional<T>> for Option<T>

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

Converts to this type from the input type.

impl<T: Parsable> FromStr for Optional<T>

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 + Parsable> 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 + Parsable> 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: Parsable> Parsable for Optional<T>

fn parse(stream: &mut ParseStream) -> Result<Self>

Attempts to parse the specified string into a value of type T.

fn parse_value(value: Self, stream: &mut ParseStream) -> Result<Self>

Attempts to parse a specific value of type T from the ParseStream.

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

The reverse of Parsable::parse, this function should return the string representation of the value.

impl<T: PartialEq + Parsable> 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 + Parsable> 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: Parsable> Spanned for Optional<T>

fn span(&self) -> Span

Returns the underlying Span of self.

impl<T: Copy + Parsable> Copy for Optional<T>

impl<T: Eq + Parsable> Eq for Optional<T>

impl<T: Parsable> StructuralPartialEq for Optional<T>