Trait clap::builder::TypedValueParser

pub trait TypedValueParser: Clone + Send + Sync + 'static {
    type Value;

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

    fn parse(
        &self,
        cmd: &Command<'_>,
        arg: Option<&Arg<'_>>,
        value: OsString
    ) -> Result<Self::Value, Error> { ... }
    fn possible_values(
        &self
    ) -> Option<Box<dyn Iterator<Item = PossibleValue<'static>> + '_>> { ... }
    fn map<T, F>(self, func: F) -> MapValueParser<Self, F>
    where
        T: Send + Sync + Clone,
        F: Fn(Self::Value) -> T + Clone,
    { ... }
}

Parse/validate argument values

Required Associated Types

type Value

Argument’s value type

Required Methods

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

Parse the argument value

When arg is None, an external subcommand value is being parsed.

Provided Methods

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

Parse the argument value

When arg is None, an external subcommand value is being parsed.

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

Reflect on enumerated value properties

Error checking should not be done with this; it is mostly targeted at user-facing applications like errors and completion.

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

Example

let cmd = Command::new("mycmd")
    .arg(
        Arg::new("flag")
            .long("flag")
            .action(clap::ArgAction::Set)
            .value_parser(
                BoolishValueParser::new()
                .map(|b| -> usize {
                    if b { 10 } else { 5 }
                })
            )
    );

let matches = cmd.clone().try_get_matches_from(["mycmd", "--flag=true", "--flag=true"]).unwrap();
assert!(matches.contains_id("flag"));
assert_eq!(
    matches.get_one::<usize>("flag").copied(),
    Some(10)
);

let matches = cmd.try_get_matches_from(["mycmd", "--flag=false"]).unwrap();
assert!(matches.contains_id("flag"));
assert_eq!(
    matches.get_one::<usize>("flag").copied(),
    Some(5)
);

Implementors

impl TypedValueParser for BoolValueParser

type Value = bool

impl TypedValueParser for BoolishValueParser

type Value = bool

impl TypedValueParser for FalseyValueParser

type Value = bool

impl TypedValueParser for NonEmptyStringValueParser

type Value = String

impl TypedValueParser for OsStringValueParser

type Value = OsString

impl TypedValueParser for PathBufValueParser

type Value = PathBuf

impl TypedValueParser for PossibleValuesParser

type Value = String

impl TypedValueParser for StringValueParser

type Value = String

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

type Value = E

impl<F, T, E> TypedValueParser for Fwhere
    F: Fn(&str) -> Result<T, E> + Clone + Send + Sync + 'static,
    E: Into<Box<dyn Error + Send + Sync + 'static>>,

type Value = T

impl<T: TryFrom<i64> + Clone + Send + Sync + 'static> TypedValueParser for RangedI64ValueParser<T>where
    <T as TryFrom<i64>>::Error: Send + Sync + 'static + Error + ToString,

type Value = T

impl<T: TryFrom<u64> + Clone + Send + Sync + 'static> TypedValueParser for RangedU64ValueParser<T>where
    <T as TryFrom<u64>>::Error: Send + Sync + 'static + Error + ToString,

type Value = T