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> 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, 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> 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) -> Selfwhere Self: Sized,

Compares and returns the maximum of two values. Read more
1.21.0 · source§

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

Compares and returns the minimum of two values. Read more
1.50.0 · source§

fn clamp(self, min: Self, max: Self) -> Selfwhere Self: Sized + 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 ==.
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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.
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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
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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§

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

Blanket Implementations§

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impl<T> Any for Twhere 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 Twhere 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 Twhere 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 Twhere 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) -> Selfwhere Owned: Into<OwnedFd>, Self: Sized + 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 Twhere 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) -> Twhere 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 Twhere 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) -> Twhere Owned: IntoSocketlike,

Constructs a new instance of Self from the given socketlike object converted from into_owned.
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impl<T, U> Into<U> for Twhere 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 Twhere 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 Twhere U: Into<T>,

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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 Twhere U: TryFrom<T>,

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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.