# Enum clap::ValueHint

source · [−]

    #[non_exhaustive]
    pub enum ValueHint {
    Show 13 variants    Unknown,
        Other,
        AnyPath,
        FilePath,
        DirPath,
        ExecutablePath,
        CommandName,
        CommandString,
        CommandWithArguments,
        Username,
        Hostname,
        Url,
        EmailAddress,
    }

Expand description

Provide shell with hint on how to complete an argument.

See Arg::value_hint to set this on an argument.

See the `clap_complete` crate for completion script generation.

Overview of which hints are supported by which shell:

Hint | zsh | fish1
--- | --- | ---
`AnyPath` | Yes | Yes
`FilePath` | Yes | Yes
`DirPath` | Yes | Yes
`ExecutablePath` | Yes | Partial
`CommandName` | Yes | Yes
`CommandString` | Yes | Partial
`CommandWithArguments` | Yes |
`Username` | Yes | Yes
`Hostname` | Yes | Yes
`Url` | Yes |
`EmailAddress` | Yes |

1. fish completions currently only support named arguments (e.g. -o or –opt), not positional arguments. ↩

## Variants (Non-exhaustive)

This enum is marked as non-exhaustive
Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

### `Unknown`

Default value if hint is not specified. Follows shell default behavior, which is usually auto-completing filenames.

### `Other`

None of the hints below apply. Disables shell completion for this argument.

### `AnyPath`

Any existing path.

### `FilePath`

Path to a file.

### `DirPath`

Path to a directory.

### `ExecutablePath`

Path to an executable file.

### `CommandName`

Name of a command, without arguments. May be relative to PATH, or full path to executable.

### `CommandString`

A single string containing a command and its arguments.

### `CommandWithArguments`

Capture the remaining arguments as a command name and arguments for that command. This is common when writing shell wrappers that execute anther command, for example `sudo` or `env`.

This hint is special, the argument must be a positional argument and have `.num_args(1..)` and Command must use `Command::trailing_var_arg(true)`. The result is that the command line `my_app ls -la /` will be parsed as `["ls", "-la", "/"]` and clap won’t try to parse the `-la` argument itself.

### `Username`

Name of a local operating system user.

### `Hostname`

Host name of a computer. Shells usually parse `/etc/hosts` and `.ssh/known_hosts` to complete hostnames.

### `Url`

Complete web address.

### `EmailAddress`

Email address.

## Trait Implementations

source

### impl Clone for ValueHint

source

#### fn clone(&self) -> ValueHint

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

source

### impl Debug for ValueHint

source

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

Formats the value using the given formatter. Read more

source

### impl Default for ValueHint

source

#### fn default() -> Self

Returns the “default value” for a type. Read more

source

### impl FromStr for ValueHint

#### type Err = String

The associated error which can be returned from parsing.

source

#### fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err>

Parses a string `s` to return a value of this type. Read more

source

### impl Hash for ValueHint

source

#### 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

source

### impl IntoResettable<ValueHint> for Option<ValueHint>

source

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

Convert to the intended resettable type

source

### impl IntoResettable<ValueHint> for ValueHint

source

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

Convert to the intended resettable type

source

### impl PartialEq<ValueHint> for ValueHint

source

#### fn eq(&self, other: &ValueHint) -> bool

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

1.0.0 · source

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

This method tests for `!=`.

source

### impl Copy for ValueHint

source

### impl Eq for ValueHint

source

### impl StructuralEq for ValueHint

source

### impl StructuralPartialEq for ValueHint

## Auto Trait Implementations

### impl RefUnwindSafe for ValueHint

### impl Send for ValueHint

### impl Sync for ValueHint

### impl Unpin for ValueHint

### impl UnwindSafe for ValueHint

## Blanket Implementations

source

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

source

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

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

source

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

const: unstable · source

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

Immutably borrows from an owned value. Read more

source

### 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

source

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

const: unstable · source

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

Returns the argument unchanged.

source

### 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.

source

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

#### type Owned = T

The resulting type after obtaining ownership.

source

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

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

source

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

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

source

### 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.

source

### 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.