Trait ctflag::FromArg

pub trait FromArg: Sized {
    fn from_arg(value: &str) -> FromArgResult<Self>;
}

Any type declared in a struct that derives ctflag::Flags must implement this trait. A blanket implementation exists for types implementing FromStr. Custom types can implement this trait directly.

enum Fruit {
    Apple,
    Orange,
}

impl FromArg for Fruit {
    fn from_arg(s: &str) -> FromArgResult<Self> {
        match s {
            "apple" => Ok(Fruit::Apple),
            "orange" => Ok(Fruit::Orange),
            _ => Err(FromArgError::with_message("bad fruit")),
        }
    }
}

Required methods

fn from_arg(value: &str) -> FromArgResult<Self>

Parses a string s to return the value of this type.

If parsing succeeds, return the value inside an Ok, otherwise return an error using [ctflag::FromArgError::with_message] inside an Err. [ctflag::FromArgError::with_message]: struct.FromArgError.html#method.with_message

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Implementors

impl<T> FromArg for T where
    T: FromStr, 

fn from_arg(s: &str) -> FromArgResult<T>

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