Trait ResultExt 

pub trait ResultExt<T, E, C: ErrorContext>: OptionExt<T, C> {
    // Required method
    fn context_with(self, f: impl FnOnce(&E) -> C) -> Result<T, C::Error>;
}

Extension trait for result types (and other types carrying errors with them).

Required Methods

fn context_with(self, f: impl FnOnce(&E) -> C) -> Result<T, C::Error>

Convert to a Result where ther error case is constructed from the given context factory which also accepts a reference to the original error.

Arguments

• f - Error context factory

Example

 #[evitable(description = "Error")]
 pub struct Context(String);

 // Later
 let io_error: std::io::Result<u8> = Err(io::Error::from(io::ErrorKind::NotFound));
 let io_ok: std::io::Result<u8> = Ok(42);

 // The functions here are called
 let error_with_source = io_error.context_with(|e| Context(format!("{:?}", e)));

 // The functions here will never be called
 let ok_result = io_ok.context_with(|e| Context(unimplemented!()));

 assert!(error_with_source.unwrap_err().source().is_some());

 ok_result.unwrap();

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<T, E: StdError + Send + Sync + 'static, C: ErrorContext> ResultExt<T, E, C> for Result<T, E>

fn context_with(self, f: impl FnOnce(&E) -> C) -> Result<T, C::Error>

Implementors