Struct clap::builder::EnumValueParser
source · Expand description
Parse an ValueEnum
value.
See also:
Example
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
enum ColorChoice {
Always,
Auto,
Never,
}
impl clap::ValueEnum for ColorChoice {
fn value_variants<'a>() -> &'a [Self] {
&[Self::Always, Self::Auto, Self::Never]
}
fn to_possible_value<'a>(&self) -> Option<clap::PossibleValue<'a>> {
match self {
Self::Always => Some(clap::PossibleValue::new("always")),
Self::Auto => Some(clap::PossibleValue::new("auto")),
Self::Never => Some(clap::PossibleValue::new("never")),
}
}
}
// 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§
Trait Implementations§
source§impl<E: Clone + ValueEnum + Clone + Send + Sync + 'static> Clone for EnumValueParser<E>
impl<E: Clone + ValueEnum + Clone + Send + Sync + 'static> Clone for EnumValueParser<E>
source§fn clone(&self) -> EnumValueParser<E>
fn clone(&self) -> EnumValueParser<E>
Returns a copy of the value. Read more
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from
source
. Read moresource§impl<E: ValueEnum + Clone + Send + Sync + 'static> TypedValueParser for EnumValueParser<E>
impl<E: ValueEnum + Clone + Send + Sync + 'static> TypedValueParser for EnumValueParser<E>
source§fn parse_ref(
&self,
cmd: &Command<'_>,
arg: Option<&Arg<'_>>,
value: &OsStr
) -> Result<Self::Value, Error>
fn parse_ref(
&self,
cmd: &Command<'_>,
arg: Option<&Arg<'_>>,
value: &OsStr
) -> Result<Self::Value, Error>
Parse the argument value Read more
source§fn possible_values(
&self
) -> Option<Box<dyn Iterator<Item = PossibleValue<'static>> + '_>>
fn possible_values(
&self
) -> Option<Box<dyn Iterator<Item = PossibleValue<'static>> + '_>>
Reflect on enumerated value properties Read more