Enum clap::builder::ValueHint

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

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)

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 .multiple_values(true) 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

impl Clone for ValueHint

fn clone(&self) -> ValueHint

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ValueHint

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

Formats the value using the given formatter.

impl Default for ValueHint

fn default() -> Self

Returns the “default value” for a type.

impl FromStr for ValueHint

type Err = String

The associated error which can be returned from parsing.

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

Parses a string s to return a value of this type.

impl Hash for ValueHint

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

Feeds this value into the given Hasher.

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

Feeds a slice of this type into the given Hasher.

impl PartialEq<ValueHint> for ValueHint

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

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

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.

impl Copy for ValueHint

impl Eq for ValueHint

impl StructuralEq for ValueHint

impl StructuralPartialEq for ValueHint