Adding `easyerr` library as a dependency

Run this command in a terminal, in your project's directory:

cargo add easyerr

To add it manually, edit your project's Cargo.toml file and add to the [dependencies] section:

easyerr = "0.1.0"

The easyerr library will be automatically available globally. Read the easyerr library documentation.

Back to the crate overview.

Readme

easyerr

crate for easier creation and transformation of error types. heavily inspired by thiserror and snafu, which are way more mature. go check them out!

goals

small library (< 1k LOC)
easy to use
doesn't show up in your public API

basic usage

(completely made up example - i'm not very creative so take this with a grain of salt)

use easyerr::prelude::*;
use std::path::PathBuf;

#[derive(Debug, Error)]
enum ValidateMessageError {
    #[error("message is too short: {f0} bytes")]
    TooShort(usize),
    #[error("message is too long: {f0} bytes")]
    TooLong(usize),
}

fn validate_message(msg: &str) -> Result<(), ValidateMessageError> {
    ensure!(msg.len() < 20, ValidateMessageError::TooShort(msg.len()));
    ensure!(msg.len() > 100, ValidateMessageError::TooLong(msg.len()));

    Ok(())
}

#[derive(Debug, Error)]
enum OpenMyStructError {
    #[error("failed to read message from {path:?}")]
    Read {
        source: std::io::Error,
        path: PathBuf,
    },
    #[error(transparent)] // delegates display and .source() to `source`
    Validation { source: ValidateMessageError },
}

struct MyStruct {
    magic_number: u32,
    message: String,
}

impl MyStruct {
    fn open_my_struct(path: PathBuf) -> Result<Self, OpenMyStructError> {
        let message = std::fs::read_to_string(&path).context(OpenMyStructCtx::Read { path })?;
        validate_message(&message).context(OpenMyStructCtx::Validation)?;

        Ok(Self {
            magic_number: 42,
            message,
        })
    }
}

the example does not show it, but structs are supported too!

Adding easyerr library as a dependency

Adding `easyerr` library as a dependency