# Enum clap::builder::Resettable

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

Expand description

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

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### impl<T: Clone> Clone for Resettable<T>

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

Returns a copy of the value. Read more

1.0.0 · source

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

Performs copy-assignment from `source`. Read more

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### impl<T: Debug> Debug for Resettable<T>

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

Formats the value using the given formatter. Read more

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

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#### fn from(other: Option<T>) -> Self

Converts to this type from the input type.

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

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#### fn from(other: T) -> Self

Converts to this type from the input type.

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### impl<T: Hash> Hash for Resettable<T>

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

Feeds this value into the given `Hasher`. Read more

1.3.0 · source

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

Feeds a slice of this type into the given `Hasher`. Read more

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### impl<T> IntoResettable<T> for Resettable<T>

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#### fn into_resettable(self) -> Resettable<T>

Convert to the intended resettable type

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### impl<T: Ord> Ord for Resettable<T>

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

This method returns an `Ordering` between `self` and `other`. Read more

1.21.0 · source

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

Compares and returns the maximum of two values. Read more

1.21.0 · source

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

Compares and returns the minimum of two values. Read more

1.50.0 · source

#### fn clamp(self, min: Self, max: Self) -> Self where
Self: PartialOrd<Self>,

Restrict a value to a certain interval. Read more

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### impl<T: PartialEq> PartialEq<Resettable<T>> for Resettable<T>

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

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

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

This method tests for `!=`.

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### impl<T: PartialOrd> PartialOrd<Resettable<T>> for Resettable<T>

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

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

1.0.0 · source

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

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

1.0.0 · source

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

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

1.0.0 · source

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

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

1.0.0 · source

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

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

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### impl<T: Copy> Copy for Resettable<T>

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### impl<T: Eq> Eq for Resettable<T>

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### impl<T> StructuralEq for Resettable<T>

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### impl<T> StructuralPartialEq for Resettable<T>

## Auto Trait Implementations

### impl<T> RefUnwindSafe for Resettable<T> where
T: RefUnwindSafe,

### impl<T> Send for Resettable<T> where
T: Send,

### impl<T> Sync for Resettable<T> where
T: Sync,

### impl<T> Unpin for Resettable<T> where
T: Unpin,

### impl<T> UnwindSafe for Resettable<T> where
T: UnwindSafe,

## Blanket Implementations

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### impl<T> Any for T where
T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more

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### impl<T> Borrow<T> for T where
T: ?Sized,

const: unstable · source

#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

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### impl<T> BorrowMut<T> for T where
T: ?Sized,

const: unstable · source

#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

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### impl<T> From<!> for T

const: unstable · source

#### fn from(t: !) -> T

Converts to this type from the input type.

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### impl<T> From<T> for T

const: unstable · source

#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T> FromFd for T where
T: From<OwnedFd>,

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#### fn from_fd(owned_fd: OwnedFd) -> T

👎 Deprecated since 1.0.0:

`FromFd::from_fd` is replaced by `From<OwnedFd>::from`

Constructs a new instance of `Self` from the given file descriptor. Read more

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#### fn from_into_fd<Owned>(into_owned: Owned) -> Self where
Owned: Into<OwnedFd>,
Self: From<OwnedFd>,

Constructs a new instance of `Self` from the given file descriptor converted from `into_owned`. Read more

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### impl<T> FromFilelike for T where
T: From<OwnedFd>,

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#### fn from_filelike(owned: OwnedFd) -> T

Constructs a new instance of `Self` from the given filelike object. Read more

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#### fn from_into_filelike<Owned>(owned: Owned) -> T where
Owned: IntoFilelike,

Constructs a new instance of `Self` from the given filelike object converted from `into_owned`. Read more

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### impl<T> FromSocketlike for T where
T: From<OwnedFd>,

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#### fn from_socketlike(owned: OwnedFd) -> T

Constructs a new instance of `Self` from the given socketlike object.

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#### fn from_into_socketlike<Owned>(owned: Owned) -> T where
Owned: IntoSocketlike,

Constructs a new instance of `Self` from the given socketlike object converted from `into_owned`. Read more

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### impl<T, U> Into<U> for T where
U: From<T>,

const: unstable · source

#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T> ToOwned for T where
T: Clone,

#### type Owned = T

The resulting type after obtaining ownership.

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#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more

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#### fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more

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### impl<T, U> TryFrom<U> for T where
U: Into<T>,

#### type Error = Infallible

The type returned in the event of a conversion error.

const: unstable · source

#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.

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### impl<T, U> TryInto<U> for T where
U: TryFrom<T>,

#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.

const: unstable · source

#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.