Struct clap::builder::FalseyValueParser

#[non_exhaustive]
pub struct FalseyValueParser {}

Parse false-like string values, everything else is true

See also:

• ValueParser::bool for assuming non-false is true
• BoolishValueParser for different human readable bool representations

Example

Usage:

let mut cmd = clap::Command::new("raw")
    .arg(
        clap::Arg::new("append")
            .value_parser(clap::builder::FalseyValueParser::new())
            .required(true)
    );

let m = cmd.try_get_matches_from_mut(["cmd", "true"]).unwrap();
let port: bool = *m.get_one("append")
    .expect("required");
assert_eq!(port, true);

Semantics:

let value_parser = clap::builder::FalseyValueParser::new();
assert_eq!(value_parser.parse_ref(&cmd, arg, OsStr::new("random")).unwrap(), true);
assert_eq!(value_parser.parse_ref(&cmd, arg, OsStr::new("100")).unwrap(), true);
assert_eq!(value_parser.parse_ref(&cmd, arg, OsStr::new("")).unwrap(), false);
assert_eq!(value_parser.parse_ref(&cmd, arg, OsStr::new("false")).unwrap(), false);
assert_eq!(value_parser.parse_ref(&cmd, arg, OsStr::new("No")).unwrap(), false);
assert_eq!(value_parser.parse_ref(&cmd, arg, OsStr::new("oFF")).unwrap(), false);
assert_eq!(value_parser.parse_ref(&cmd, arg, OsStr::new("0")).unwrap(), false);

Implementations

impl FalseyValueParser

pub fn new() -> FalseyValueParser

Parse false-like string values, everything else is true

Trait Implementations

impl Clone for FalseyValueParser

fn clone(&self) -> FalseyValueParser

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for FalseyValueParser

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

Formats the value using the given formatter.

impl Default for FalseyValueParser

fn default() -> FalseyValueParser

Returns the “default value” for a type.

impl TypedValueParser for FalseyValueParser

type Value = bool

Argument’s value type

fn parse_ref( &self, cmd: &Command, _arg: Option<&Arg>, value: &OsStr, ) -> Result<<FalseyValueParser as TypedValueParser>::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 + Sync + Send>>,

Adapt a TypedValueParser from one value to another

impl Copy for FalseyValueParser

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: 0 bytes