Trait ResultAtExt 

pub trait ResultAtExt<T, E> {
    // Required methods
    fn at(self) -> Result<T, At<E>>;
    fn at_str(self, msg: &'static str) -> Result<T, At<E>>;
    fn at_string(self, f: impl FnOnce() -> String) -> Result<T, At<E>>;
    fn at_data<C>(self, f: impl FnOnce() -> C) -> Result<T, At<E>>
       where C: Display + Send + Sync + 'static;
    fn at_debug<C>(self, f: impl FnOnce() -> C) -> Result<T, At<E>>
       where C: Debug + Send + Sync + 'static;
    fn at_aside_error<Err>(self, err: Err) -> Result<T, At<E>>
       where Err: Error + Send + Sync + 'static;
    fn at_error<Err>(self, err: Err) -> Result<T, At<E>>
       where Err: Error + Send + Sync + 'static;
    fn at_crate(self, info: &'static AtCrateInfo) -> Result<T, At<E>>;
    fn at_fn<F>(self, marker: F) -> Result<T, At<E>>
       where F: Fn();
    fn at_named(self, name: &'static str) -> Result<T, At<E>>;
    fn map_err_at<E2, F>(self, f: F) -> Result<T, At<E2>>
       where F: FnOnce(E) -> E2;
}

Extension trait for adding location tracking to Result<T, At<E>>.

Example

use whereat::{at, At, ResultAtExt};

#[derive(Debug)]
enum MyError { Oops }

fn inner() -> Result<(), At<MyError>> {
    Err(at(MyError::Oops))
}

fn outer() -> Result<(), At<MyError>> {
    inner().at()?;
    Ok(())
}

Required Methods

fn at(self) -> Result<T, At<E>>

Add the caller’s location to the error trace if this is Err.

fn at_str(self, msg: &'static str) -> Result<T, At<E>>

Add static string context to last location (or create one if empty).

fn at_string(self, f: impl FnOnce() -> String) -> Result<T, At<E>>

Add lazily-computed string context to last location (or create one if empty).

fn at_data<C>(self, f: impl FnOnce() -> C) -> Result<T, At<E>>

where C: Display + Send + Sync + 'static,

Add lazily-computed typed context (Display) to last location (or create one if empty).

fn at_debug<C>(self, f: impl FnOnce() -> C) -> Result<T, At<E>>

where C: Debug + Send + Sync + 'static,

Add lazily-computed typed context (Debug) to last location (or create one if empty).

fn at_aside_error<Err>(self, err: Err) -> Result<T, At<E>>

where Err: Error + Send + Sync + 'static,

Attach a related error as diagnostic context on the last frame.

The attached error is not part of the .source() chain — it is only visible via trace display and .contexts() iteration.

fn at_error<Err>(self, err: Err) -> Result<T, At<E>>

where Err: Error + Send + Sync + 'static,

👎Deprecated since 0.1.4:

Renamed to at_aside_error(). The attached error is NOT part of the .source() chain.

Attach an error as diagnostic context (not in .source() chain).

fn at_crate(self, info: &'static AtCrateInfo) -> Result<T, At<E>>

Add crate boundary marker to last location (or create one if empty).

fn at_fn<F>(self, marker: F) -> Result<T, At<E>>

where F: Fn(),

Add a location frame with the caller’s function name as context.

Captures both file:line:col AND the function name at zero runtime cost. Pass an empty closure || {} - its type includes the parent function name.

fn at_named(self, name: &'static str) -> Result<T, At<E>>

Add a location frame with an explicit name as context.

Like at_fn but with an explicit label.

fn map_err_at<E2, F>(self, f: F) -> Result<T, At<E2>>

where F: FnOnce(E) -> E2,

Convert the error type while preserving the trace.

This is a convenience method that combines map_err with At::map_error.

Example

use whereat::{at, At, ResultAtExt};

#[derive(Debug)]
struct InternalError;
#[derive(Debug)]
struct PublicError;

fn internal() -> Result<(), At<InternalError>> {
    Err(at(InternalError))
}

fn public() -> Result<(), At<PublicError>> {
    // Clean conversion that preserves trace
    internal().map_err_at(|_| PublicError)?;
    Ok(())
}

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl<T, E> ResultAtExt<T, E> for Result<T, At<E>>

fn at(self) -> Result<T, At<E>>

fn at_str(self, msg: &'static str) -> Result<T, At<E>>

fn at_string(self, f: impl FnOnce() -> String) -> Result<T, At<E>>

fn at_data<C>(self, f: impl FnOnce() -> C) -> Result<T, At<E>>

where C: Display + Send + Sync + 'static,

fn at_debug<C>(self, f: impl FnOnce() -> C) -> Result<T, At<E>>

where C: Debug + Send + Sync + 'static,

fn at_aside_error<Err>(self, err: Err) -> Result<T, At<E>>

where Err: Error + Send + Sync + 'static,

fn at_error<Err>(self, err: Err) -> Result<T, At<E>>

where Err: Error + Send + Sync + 'static,

👎Deprecated since 0.1.4:

Renamed to at_aside_error(). The attached error is NOT part of the .source() chain.

fn at_crate(self, info: &'static AtCrateInfo) -> Result<T, At<E>>

fn at_fn<F>(self, marker: F) -> Result<T, At<E>>

where F: Fn(),

fn at_named(self, name: &'static str) -> Result<T, At<E>>

fn map_err_at<E2, F>(self, f: F) -> Result<T, At<E2>>

where F: FnOnce(E) -> E2,

Implementors