Struct clap_builder::builder::PossibleValuesParser

pub struct PossibleValuesParser(/* private fields */);

Verify the value is from an enumerated set of PossibleValue.

See also:

• EnumValueParser for directly supporting ValueEnum types
• TypedValueParser::map for adapting values to a more specialized type, like an external enums that can’t implement ValueEnum

Example

Usage:

let mut cmd = clap::Command::new("raw")
    .arg(
        clap::Arg::new("color")
            .value_parser(clap::builder::PossibleValuesParser::new(["always", "auto", "never"]))
            .required(true)
    );

let m = cmd.try_get_matches_from_mut(["cmd", "always"]).unwrap();
let port: &String = m.get_one("color")
    .expect("required");
assert_eq!(port, "always");

Semantics:

let value_parser = clap::builder::PossibleValuesParser::new(["always", "auto", "never"]);
assert!(value_parser.parse_ref(&cmd, arg, OsStr::new("random")).is_err());
assert!(value_parser.parse_ref(&cmd, arg, OsStr::new("")).is_err());
assert_eq!(value_parser.parse_ref(&cmd, arg, OsStr::new("always")).unwrap(), "always");
assert_eq!(value_parser.parse_ref(&cmd, arg, OsStr::new("auto")).unwrap(), "auto");
assert_eq!(value_parser.parse_ref(&cmd, arg, OsStr::new("never")).unwrap(), "never");

Implementations

impl PossibleValuesParser

pub fn new(values: impl Into<PossibleValuesParser>) -> Self

Verify the value is from an enumerated set of PossibleValue.

Trait Implementations

impl Clone for PossibleValuesParser

fn clone(&self) -> PossibleValuesParser

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for PossibleValuesParser

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

Formats the value using the given formatter.

impl<I, T> From<I> for PossibleValuesParser

where I: IntoIterator<Item = T>, T: Into<PossibleValue>,

fn from(values: I) -> Self

Converts to this type from the input type.

impl TypedValueParser for PossibleValuesParser

type Value = String

Argument’s value type

fn parse_ref( &self, cmd: &Command, arg: Option<&Arg>, value: &OsStr, ) -> Result<Self::Value, Error>

Parse the argument value

fn parse( &self, cmd: &Command, arg: Option<&Arg>, value: OsString, ) -> Result<String, Error>

Parse the argument value

fn possible_values( &self, ) -> Option<Box<dyn Iterator<Item = PossibleValue> + '_>>

Reflect on enumerated value properties

fn parse_ref_( &self, cmd: &Command, arg: Option<&Arg>, value: &OsStr, _source: ValueSource, ) -> Result<Self::Value, Error>

Parse the argument value

fn parse_( &self, cmd: &Command, arg: Option<&Arg>, value: OsString, _source: ValueSource, ) -> Result<Self::Value, Error>

Parse the argument value

fn map<T, F>(self, func: F) -> MapValueParser<Self, F>

where T: Send + Sync + Clone, F: Fn(Self::Value) -> T + Clone,

Adapt a TypedValueParser from one value to another

fn try_map<T, E, F>(self, func: F) -> TryMapValueParser<Self, F>

where F: Fn(Self::Value) -> Result<T, E> + Clone + Send + Sync + 'static, T: Send + Sync + Clone, E: Into<Box<dyn Error + Send + Sync + 'static>>,

Adapt a TypedValueParser from one value to another

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 24 bytes