Enum clap::builder::Resettable

pub enum Resettable<T> {
    Value(T),
    Reset,
}

Clearable builder value

This allows a builder function to both accept any value that can Into::into T (like &str into OsStr) as well as None to reset it to the default. This is needed to workaround a limitation where you can’t have a function argument that is impl Into<Option<T>> where T is impl Into<S> accept None as its type is ambiguous.

Example

fn common() -> Command {
    Command::new("cli")
        .arg(Arg::new("input").short('i').long("input"))
}
let mut command = common();
command.mut_arg("input", |arg| arg.short(None));

Variants

Value(T)

Overwrite builder value

Reset

Reset builder value

Trait Implementations

impl<T> Clone for Resettable<T>where T: Clone,

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

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T> Debug for Resettable<T>where T: Debug,

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

Formats the value using the given formatter.

impl<T> From<Option<T>> for Resettable<T>

fn from(other: Option<T>) -> Resettable<T>

Converts to this type from the input type.

impl<T> From<T> for Resettable<T>

fn from(other: T) -> Resettable<T>

Converts to this type from the input type.

impl<T> Hash for Resettable<T>where T: Hash,

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

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> IntoResettable<T> for Resettable<T>

fn into_resettable(self) -> Resettable<T>

Convert to the intended resettable type

impl<T> Ord for Resettable<T>where T: Ord,

fn cmp(&self, other: &Resettable<T>) -> Ordering

This method returns an Ordering between self and other.

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

Compares and returns the maximum of two values.

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

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Selfwhere Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval.

impl<T> PartialEq<Resettable<T>> for Resettable<T>where T: PartialEq<T>,

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

This method tests for self and other values to be equal, and is used by ==.

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

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

impl<T> PartialOrd<Resettable<T>> for Resettable<T>where T: PartialOrd<T>,

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

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

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

This method tests less than (for self and other) and is used by the < operator.

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

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

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

This method tests greater than (for self and other) and is used by the > operator.

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

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

impl<T> Copy for Resettable<T>where T: Copy,

impl<T> Eq for Resettable<T>where T: Eq,

impl<T> StructuralEq for Resettable<T>

impl<T> StructuralPartialEq for Resettable<T>