Crate error_rail 

Composable, metadata-friendly error handling utilities.

error-rail focuses on three pillars:

1. Structured context – enrich any error with layered metadata using context! helpers and macros such as location! and tag!.
2. Composable collectors – aggregate successes/failures with the validation module and convert between Result, Validation, and ComposableError via convert.
3. Ergonomic traits/macros – glue traits in traits and shortcuts in macros keep the API light-weight.

Each submodule re-exports its public surface from here, so consumers can simply depend on error_rail::* or pick focused pieces as needed.

Examples

Basic Error with Context

use error_rail::{ComposableError, ErrorContext, context, location, tag};

let err = ComposableError::new("database connection failed")
    .with_context(tag!("db"))
    .with_context(location!())
    .set_code(500);

Validation Accumulation

use error_rail::validation::Validation;

let v1: Validation<&str, i32> = Validation::Valid(10);
let v2: Validation<&str, i32> = Validation::invalid("error");
let combined: Validation<&str, Vec<i32>> = vec![v1, v2].into_iter().collect();
assert!(combined.is_invalid());

Error Pipeline

use error_rail::{ErrorPipeline, context};

let result = ErrorPipeline::<i32, &str>::new(Err("failed"))
    .with_context(context!("operation: load_config"))
    .with_context(context!("user_id: 42"))
    .finish_boxed();

if let Err(err) = result {
    eprintln!("{}", err.error_chain());
    // Output: user_id: 42 -> operation: load_config -> failed
}

Re-exports

pub use context::*;

pub use convert::*;

pub use traits::*;

pub use types::*;

pub use validation::*;

Modules

context

Error context management and accumulation Helpers for attaching rich context metadata to errors.

convert

Error type conversions between Result, Validation, and ComposableError Conversion helpers between Result, Validation, and ComposableError.

macros

Error handling macros for context creation Ergonomic macros for creating lazy or structured ErrorContext.

traits

Core traits for error handling and composition Core traits for error handling and composition.

types

ComposableError and error context structures Error types and utilities.

validation

Validation type and associated traits for error accumulation Validation types and utilities for accumulating errors.

Macros

backtrace

Captures the current backtrace as lazy error context.

context

Creates a lazily-evaluated error context that defers string formatting.

impl_error_context

Implements IntoErrorContext for a custom type.

location

Captures the current source file and line number as error context.

metadata

Creates a key-value metadata pair for structured error context.

rail

Wraps a Result-producing expression or block and converts it into a BoxedComposableResult.

tag

Creates a categorical tag for error classification.