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## Resettable

# Enum Resettable

Source

    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§

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### Value(T)

Overwrite builder value

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### Reset

Reset builder value

## Trait Implementations§

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

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

Returns a duplicate of the value. Read more
1.0.0 (const: unstable) · Source§

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

Performs copy-assignment from `source`. Read more
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### impl<T> Copy for Resettable<T>
where T: Copy,

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

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

Formats the value using the given formatter. Read more
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### impl<T> Eq for Resettable<T>
where T: Eq,

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

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

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) -> Resettable<T>

Converts to this type from the input type.
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### impl<T> Hash for Resettable<T>
where T: Hash,

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

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, Self: Sized,

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 for Resettable<T>
where T: Ord,

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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 (const: unstable) · Source§

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

Compares and returns the maximum of two values. Read more
1.21.0 (const: unstable) · Source§

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

Compares and returns the minimum of two values. Read more
1.50.0 (const: unstable) · Source§

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

Restrict a value to a certain interval. Read more
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### impl<T> PartialEq for Resettable<T>
where T: PartialEq,

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

Equality operator `==`. Read more
1.0.0 (const: unstable) · Source§

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

Inequality operator `!=`. Read more
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### impl<T> PartialOrd for Resettable<T>
where T: PartialOrd,

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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 (const: unstable) · Source§

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

Tests less than (for `self` and `other`) and is used by the `<` operator. Read more
1.0.0 (const: unstable) · Source§

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

Tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more
1.0.0 (const: unstable) · Source§

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

Tests greater than (for `self` and `other`) and is used by the `>` operator. Read more
1.0.0 (const: unstable) · Source§

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

Tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more
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### impl<T> StructuralPartialEq for Resettable<T>
where T: PartialEq,

## Auto Trait Implementations§

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

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

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

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

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

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

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### 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,

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#### 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,

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

Mutably borrows from an owned value. Read more
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### impl<T> CloneToUninit for T
where T: Clone,

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#### unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (`clone_to_uninit`)
Performs copy-assignment from `self` to `dest`. Read more
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### impl<T> From<!> for T

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

Converts to this type from the input type.
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### impl<T> From<T> for T

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

Returns the argument unchanged.

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

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#### 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,

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#### 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>,

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#### type Error = Infallible

The type returned in the event of a conversion error.
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#### 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>,

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

The type returned in the event of a conversion error.
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#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.