pub struct PossibleValue { /* private fields */ }
Expand description

A possible value of an argument.

This is used for specifying possible values of Args.

See also PossibleValuesParser

NOTE: Most likely you can use strings, rather than PossibleValue as it is only required to hide single values from help messages and shell completions or to attach help to possible values.

Examples

let cfg = Arg::new("config")
    .action(ArgAction::Set)
    .value_name("FILE")
    .value_parser([
        PossibleValue::new("fast"),
        PossibleValue::new("slow").help("slower than fast"),
        PossibleValue::new("secret speed").hide(true)
    ]);

Implementations§

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impl PossibleValue

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pub fn new(name: impl Into<Str>) -> Self

Create a PossibleValue with its name.

The name will be used to decide whether this value was provided by the user to an argument.

NOTE: In case it is not hidden it will also be shown in help messages for arguments that use it as a possible value and have not hidden them through Arg::hide_possible_values(true).

Examples
PossibleValue::new("fast")
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pub fn help(self, help: impl IntoResettable<StyledStr>) -> Self

Sets the help description of the value.

This is typically displayed in completions (where supported) and should be a short, one-line description.

Examples
PossibleValue::new("slow")
    .help("not fast")
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pub fn hide(self, yes: bool) -> Self

Hides this value from help and shell completions.

This is an alternative to hiding through Arg::hide_possible_values(true), if you only want to hide some values.

Examples
PossibleValue::new("secret")
    .hide(true)
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pub fn alias(self, name: impl IntoResettable<Str>) -> Self

Sets a hidden alias for this argument value.

Examples
PossibleValue::new("slow")
    .alias("not-fast")
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pub fn aliases(self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self

Sets multiple hidden aliases for this argument value.

Examples
PossibleValue::new("slow")
    .aliases(["not-fast", "snake-like"])
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impl PossibleValue

Reflection

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pub fn get_name(&self) -> &str

Get the name of the argument value

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pub fn get_help(&self) -> Option<&StyledStr>

Get the help specified for this argument, if any

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pub fn is_hide_set(&self) -> bool

Report if PossibleValue::hide is set

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pub fn get_name_and_aliases(&self) -> impl Iterator<Item = &str> + '_

Returns all valid values of the argument value.

Namely the name and all aliases.

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pub fn matches(&self, value: &str, ignore_case: bool) -> bool

Tests if the value is valid for this argument value

The value is valid if it is either the name or one of the aliases.

Examples
let arg_value = PossibleValue::new("fast").alias("not-slow");

assert!(arg_value.matches("fast", false));
assert!(arg_value.matches("not-slow", false));

assert!(arg_value.matches("FAST", true));
assert!(!arg_value.matches("FAST", false));

Trait Implementations§

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impl Clone for PossibleValue

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fn clone(&self) -> PossibleValue

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for PossibleValue

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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 Default for PossibleValue

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fn default() -> PossibleValue

Returns the “default value” for a type. Read more
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impl<S: Into<Str>> From<S> for PossibleValue

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fn from(s: S) -> Self

Converts to this type from the input type.
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impl PartialEq<PossibleValue> for PossibleValue

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fn eq(&self, other: &PossibleValue) -> 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 Eq for PossibleValue

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impl StructuralEq for PossibleValue

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impl StructuralPartialEq for PossibleValue

Auto Trait Implementations§

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<T> for T

const: unstable · source§

fn from(t: T) -> T

Returns the argument unchanged.

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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.