Trait ValueEnum

pub trait ValueEnum: Sized + Clone {
    // Required methods
    fn value_variants<'a>() -> &'a [Self];
    fn to_possible_value(&self) -> Option<PossibleValue>;

    // Provided method
    fn from_str(input: &str, ignore_case: bool) -> Result<Self, String> { ... }
}

Parse arguments into enums.

When deriving Parser, a field whose type implements ValueEnum can have the attribute #[arg(value_enum)] which will

• Call EnumValueParser
• Allowing using the #[arg(default_value_t)] attribute without implementing Display.

NOTE: Deriving requires the derive feature flag

Required Methods

fn value_variants<'a>() -> &'a [Self]

All possible argument values, in display order.

fn to_possible_value(&self) -> Option<PossibleValue>

The canonical argument value.

The value is None for skipped variants.

Provided Methods

fn from_str(input: &str, ignore_case: bool) -> Result<Self, String>

Parse an argument into Self.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl ValueEnum for ColorChoice