Struct EnumValueParser

pub struct EnumValueParser<E: ValueEnum + Clone + Send + Sync + 'static>(/* private fields */);

Parse an ValueEnum value.

See also:

• PossibleValuesParser

Example

// Usage
let mut cmd = clap::Command::new("raw")
    .arg(
        clap::Arg::new("color")
            .value_parser(clap::builder::EnumValueParser::<ColorChoice>::new())
            .required(true)
    );

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

// Semantics
let value_parser = clap::builder::EnumValueParser::<ColorChoice>::new();
// or
let value_parser = clap::value_parser!(ColorChoice);
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(), ColorChoice::Always);
assert_eq!(value_parser.parse_ref(&cmd, arg, OsStr::new("auto")).unwrap(), ColorChoice::Auto);
assert_eq!(value_parser.parse_ref(&cmd, arg, OsStr::new("never")).unwrap(), ColorChoice::Never);

Implementations

impl<E: ValueEnum + Clone + Send + Sync + 'static> EnumValueParser<E>

pub fn new() -> Self

Parse an ValueEnum

Trait Implementations

impl<E: Clone + ValueEnum + Clone + Send + Sync + 'static> Clone for EnumValueParser<E>

fn clone(&self) -> EnumValueParser<E>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<E: Debug + ValueEnum + Clone + Send + Sync + 'static> Debug for EnumValueParser<E>

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

Formats the value using the given formatter.

impl<E: ValueEnum + Clone + Send + Sync + 'static> Default for EnumValueParser<E>

fn default() -> Self

Returns the “default value” for a type.

impl<E: ValueEnum + Clone + Send + Sync + 'static> TypedValueParser for EnumValueParser<E>

type Value = E

Argument’s value type

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

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