Trait lexopt::ValueExt

pub trait ValueExt: Sealed {
    fn parse<T: FromStr>(&self) -> Result<T, Error>
    where
        T::Err: Into<Box<dyn Error + Send + Sync + 'static>>;
    fn parse_with<F, T, E>(&self, func: F) -> Result<T, Error>
    where
        F: FnOnce(&str) -> Result<T, E>,
        E: Into<Box<dyn Error + Send + Sync + 'static>>;
    fn string(self) -> Result<String, Error>;
}

An optional extension trait with methods for parsing OsStrings.

They may fail in two cases:

• The value cannot be decoded because it’s invalid unicode (Error::NonUnicodeValue)
• The value can be decoded, but parsing fails (Error::ParsingFailed)

If parsing fails the error will be wrapped in lexopt’s own Error type.

Required Methods

fn parse<T: FromStr>(&self) -> Result<T, Error>where
    T::Err: Into<Box<dyn Error + Send + Sync + 'static>>,

Decode the value and parse it using FromStr.

This will fail if the value is not valid unicode or if the subsequent parsing fails.

fn parse_with<F, T, E>(&self, func: F) -> Result<T, Error>where
    F: FnOnce(&str) -> Result<T, E>,
    E: Into<Box<dyn Error + Send + Sync + 'static>>,

Decode the value and parse it using a custom function.

fn string(self) -> Result<String, Error>

Convert the OsString into a String if it’s valid Unicode.

This is like OsString::into_string but returns an Error::NonUnicodeValue on error instead of the original OsString. This makes it easier to propagate the failure with libraries like anyhow.

Implementations on Foreign Types

impl ValueExt for OsString

fn parse<T: FromStr>(&self) -> Result<T, Error>where
    T::Err: Into<Box<dyn Error + Send + Sync + 'static>>,

fn parse_with<F, T, E>(&self, func: F) -> Result<T, Error>where
    F: FnOnce(&str) -> Result<T, E>,
    E: Into<Box<dyn Error + Send + Sync + 'static>>,

fn string(self) -> Result<String, Error>

Implementors