Trait ValueExt

pub trait ValueExt: Sealed {
    // Required methods
    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.

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.

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