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//! > “Times are bad. Children no longer obey their parents, and everyone is
//! > writing an error handling library.”
//! > — Cicero
//!
//!
//! fast, cheap, and out of control exceptions for rust.
//!
//! # Usage
//!
//! First, add this to your `Cargo.toml`:
//! ```toml
//! [dependencies]
//! eliza_error = "0.99.0";
//! ```
//!
//! You can now throw exceptions!
//! ```rust
//! use eliza_error::{Error, throw};
//!
//! # fn is_everything_terrible() -> bool { true }
//! fn my_great_function() -> Result<(), Error> {
//!     if is_everything_terrible() {
//!         throw!("everything is terrible!");
//!     }
//!     Ok(())
//! }
//! ```
//! Eliza errors also work fine with errors from the standard library.
//! ```rust
//! use eliza_error::{Error, throw};
//! use std::fs::File;
//! use std::io::prelude::*;
//!
//! fn look_at_file() -> Result<(), Error> {
//!     let mut file = File::open("this_file_doesnt_exist.txt")?;
//!     let mut contents = String::new();
//!     file.read_to_string(&mut contents)?;
//!     if contents == "everything is terrible!!!" {
//!         throw!("wow, everything is still terrible!!!");
//!     }
//!     Ok(())
//! }
//! ```
//!
//! # Why should I use this?
//!
//! - `eliza_error` has no dependencies!
//! - `eliza_error` can throw exceptions!
//! - `eliza_error` [will support backtraces soon][backtrace]!
//!
//! [backtrace]: https://github.com/rust-lang/rust/issues/53487

/// Construct a new error with a message.
#[macro_export]
macro_rules! fmt_error {
    ($($arg:tt)*) => { $crate::Error::from($crate::ElizaError::from(format!($($arg)*))) };
}

/// Throw an error with a message, returning early from the current function.
#[macro_export]
macro_rules! throw {
    ($($arg:tt)*) => { return Err($crate::Error::from($crate::ElizaError::from(format!($($arg)*)))) };
}

/// An error.
pub type Error = Box<dyn std::error::Error + Send + Sync + 'static>;

/// A cool eliza error, with a message.
#[doc(hidden)]
pub struct ElizaError {
    message: String,
}

impl std::fmt::Display for ElizaError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.pad(&self.message)
    }
}

impl std::fmt::Debug for ElizaError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.pad(&self.message)
    }
}

impl std::error::Error for ElizaError {}

impl From<String> for ElizaError {
    fn from(message: String) -> Self {
        Self { message }
    }
}