Crate easy_error[−][src]
Easy-error
This crate is a lightweight error handling library meant to play well with
the standard Error
trait. It is designed for quick prototyping or for
Command-line applications where any error will simply bubble up to the user.
There are four major components of this crate:
- A basic, string-based error type that is meant for either quick prototyping or human-facing errors.
- A nice way to iterate over the causes of an error.
- Some macros that make returning errors slightly more ergonomic.
- A “termination” type that produces nicely formatted error messages when
returned from the
main
function.
Rust Version Requirements
The current version requires Rustc 1.46 or newer. In general, this crate will be compilable with the Rustc version available on the oldest supported Ubuntu LTS release. Any change that requires a newer version of Rustc than what is available on the oldest supported Ubuntu LTS will be considered a breaking change.
Example
use std::{fs::File, io::Read}; use easy_error::{bail, ensure, Error, ResultExt, Terminator}; fn from_file() -> Result<i32, Error> { let file_name = "example.txt"; let mut file = File::open(file_name).context("Could not open file")?; let mut contents = String::new(); file.read_to_string(&mut contents).context("Unable to read file")?; contents.trim().parse().context("Could not parse file") } fn validate(value: i32) -> Result<(), Error> { ensure!(value > 0, "Value must be greater than zero (found {})", value); if value % 2 == 1 { bail!("Only even numbers can be used"); } Ok(()) } fn main() -> Result<(), Terminator> { let value = from_file().context("Unable to get value from file")?; validate(value).context("Value is not acceptable")?; println!("Value = {}", value); Ok(()) }
Macros
bail | Exits a function early with an |
ensure | Exits a function early with an |
format_err | Creates an |
Structs
Causes | An iterator over the causes of an error. |
Error | An error that is a human-targetted string plus an optional cause. |
Terminator | An error that wraps all other error types for a nicer debug output. |
Traits
ErrorExt | Extension methods to |
ResultExt | Extension methods to the |
Functions
err_msg | Creates an error message from the provided string. |
Type Definitions
Result |