# error-doc

A simple proc macro to generate `#[doc]` comments from `#[error]` messages

## Usage

The `errors` macro derives `thiserror::Error` and `core::fmt::Debug` traits, and automatically generates missing documents for error variants from error messages.

Using `error_doc` macro, you can also derive `Error` and `Debug` trait separately.

### Example

```rust
#[error_doc::errors]
pub enum SomeError {
    #[error("failed to open config file")]
    OpenFile(#[from] std::io::Error),
    #[error(transparent)]
    #[doc = "Database error"]
    Database(#[from] sqlx::Error),
    #[error("unexpected value: `{0}`")]
    #[doc = "Unexpected value is provided"]
    UnexpectedValue(u16),
    #[error("some other error")]
    Other,
}
```

and

```rust
#[error_doc::error_doc]
#[derive(thiserror::Error, Debug)]
pub enum SomeError {
    #[error("failed to open config file")]
    OpenFile(#[from] std::io::Error),
    #[error(transparent)]
    #[doc = "Database error"]
    Database(#[from] sqlx::Error),
    #[error("unexpected value: `{0}`")]
    #[doc = "Unexpected value is provided"]
    UnexpectedValue(u16),
    #[error("some other error")]
    Other,
}
```

generates

```rust
#[derive(thiserror::Error, Debug)]
pub enum SomeError {
    #[error("failed to open config file")]
    #[doc = "Failed to open config file"]
    OpenFile(#[from] std::io::Error),
    #[error(transparent)]
    #[doc = "Database error"]
    Database(#[from] sqlx::Error),
    #[error("unexpected value: `{0}`")]
    #[doc = "Unexpected value is provided"]
    UnexpectedValue(u16),
    #[error("some other error")]
    #[doc = "Some other error"]
    Other,
}
```

## License

Licensed under either of

 * MIT license
   ([LICENSE-MIT](./LICENSE-MIT) or https://opensource.org/licenses/MIT)
 * Apache License, Version 2.0
   ([LICENSE-APACHE](./LICENSE-APACHE) or https://www.apache.org/licenses/LICENSE-2.0)

at your option.

### Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.