Crate mabe

Mabe is a simple framework for creating debug-friendly error enums in Rust. Each variant in the enum can encapsulate an error and a debug message, and errors are presented in a structured format, displaying the messages defined for the variant. This allows for a more detailed and clear debugging process.

Functionally, this crate is a procedural macro that provides a derive macro called Mabe, which is used to generate the debug-friendly error enums.

Examples

Here is a simple example of how to create a debug-friendly error enum:

use mabe::Mabe;

#[derive(Mabe)]
pub enum ServerError {
    #[error("You are not authorized to access this resource.")]
    #[debug("Try using a different account.")]
    Unauthorized,
}

let error = ServerError::Unauthorized;
println!("{}", error);

Output:
[error] You are not authorized to access this resource.
[debug] Try using a different account.

You can also interpolate the values of variant fields in the error and debug messages as shown below:

use mabe::Mabe;

#[derive(Mabe)]
pub enum ServerError {
    // Interpolates the values of the 1st and 2nd field in the error message.
    #[error("Network failure. --> Code: {0}: {1}.")]
    NetworkFailure(u32, String),

    // Interpolates the value of the `cause` field in the error message.
    #[error("Connection lost. --> {cause}.")]
    // Interpolates the value of the `retry_in` field in the debug message.
    #[debug("Retry in {retry_in} seconds.")]
    ConnectionLost { cause: String, retry_in: u32 }
}

let error1 = ServerError::NetworkFailure(404, "Not Found".to_string());
println!("{}", error1);

let error2 = ServerError::ConnectionLost { cause: "Server down".to_string(), retry_in: 10 };
println!("{}", error2);

Output:
[error] Network failure. --> Code: 404: Not Found.

[error] Connection lost --> Server down.
[debug] Retry in 10 seconds.

Cargo Features

The following is a list of Cargo features that can be enabled or disabled in the Cargo.toml file:

• colorize: Adds colors to the prefixes of the error and debug messages (i.e. to [error] and [debug]) when they are printed. This feature only works with ANSI-compatible terminals.

Derive Macros

Mabe

The derive macro that creates the debug-friendly error enums. It provides an error and a debug attribute for each variant of the enum, which can be used to define the error and debug messages respectively. The macro also automatically generates implementations for the Debug, Display, and Error traits.